bluuebunny/crossref_metadata_2025 huggingface dataset:
LPAM: A lightweight medical segmentation network based on Mamba improved by prompt attention
Authors: Hu Kaiqi , Xu Chudong
Published: July 2024

Presently, State Space Models (SSMs), including frameworks like Mamba, have been incorporated into the realm of computer vision. These models not only sustain remote interactions and encapsulate global semantic information effectively, but also preserve linear computational complexity, offering a balance between performance and computational efficiency. Given that Mamba inherently adheres to the principle of selectivity when constructing sequence models, the goal is to further unleash the potential of Mamba through this innovative combination of convolution and self‐attention, improve accuracy and minimize the number of parameters while achieving linear complexity. Mamba is employed as an encoder to distill semantic information from the image, and it is supplemented with convolutional blocks, thereby conserving the details of the image. Concurrently, embedding prompts at a deeper level enhances its adaptability to cater to diverse requirements. Lastly, a bidirectional attention mechanism is incorporated for inference, striving to retain both global connections and local details to the maximum extent. This culminates in a novel, lightweight medical segmentation model. Exhaustive experiments were executed on six public datasets. The empirical results show that the proposed model exhibits competitive performance in medical image segmentation tasks.
Circular synthetic aperture radar sub‐aperture angle information complementation based on azimuth‐controllable generative adversarial network
Authors: Li Bingxuan , Ma Yanheng , Chu Lina , Li Wei , Shi Yuanping
Published: July 2024

A conditional generative adversarial network (CGAN) framework is proposed to address the issue of incomplete circular synthetic aperture radar (CSAR) azimuthal information due to motion errors. Specifically, the authors propose a novel CGAN architecture that can control the azimuth angle for arbitrary angle generation, capable of complementing missing CSAR sub‐aperture information. The network incorporates angular labels for various scenarios and integrates a dynamic region‐aware convolution (DRconv) module. Additionally, to counteract the common challenge of mode collapse in GAN training, a mode seeking regularisation technique is innovativrly introduced into the authors’ loss function. The efficacy of the proposed network is rigorously tested using both the MSTAR dataset and an X‐band SAR dataset. The results demonstrate that the authors’ network can generate high‐fidelity SAR images with controllable azimuths, closely resembling authentic images. Furthermore, the proposed method excels in complementing missing CSAR sub‐aperture information, effectively supplying the lost angular information due to motion errors. A new technical approach for SAR image generation is not only offered but it also has the potential to significantly expand SAR datasets. This advancement is expected to enhance the quality and utility of SAR imagery in applications such as surveillance, reconnaissance, and environmental monitoring.
Multi‐source DOA estimation based on multi‐UAV collaboration in complex GNSS spoofing environments
Authors: Zhou Jianwei , Wang Wenjie , Zhang Chenhao
Published: July 2024

Unmanned Aerial Vehicles (UAVs) are widely used in both military and civilian sectors due to their maneuverability and versatility. However, UAVs rely on the Global Navigation Satellite System (GNSS) for real‐time accurate navigation and are therefore vulnerable to attacks, particularly spoofing attacks, in GNSS‐challenging environments. Furthermore, UAV payloads are generally limited to carrying only a single antenna, significantly restricting the spatial Degrees of Freedom (DoFs) available. A new scheme is presented to address the challenges posed by multiple spoofing sources for UAV GNSS navigation. Unlike conventional multi‐antenna techniques, our approach extends centralised multi‐antenna Direction of Arrival (DOA) estimation to distributed scenarios using UAV collaboration techniques. The multi‐source DOA estimation of GNSS spoofing is achieved using the space‐time DOA matrix (ST‐DOAMatrix) technique, which enhances system resilience and spatial DoFs. Simulation results validate the effectiveness of the proposed method and demonstrate the feasibility and potential of the technique in ensuring the proper and safe operation of UAVs using GNSS navigation.
Large Interferometer For Exoplanets (LIFE)
Authors: Alei E. , Quanz S. P. , Konrad B. S. , Garvin E. O. , Kofman V. , Mandell A. , Angerhausen D. , Mollière P. , Meyer M. R. , Robinson T. , Rugheimer S. ,   the LIFE Collaboration
Published: July 2024

Context. Following the recommendations to NASA (in the Astro2020 Decadal survey) and ESA (through the Voyage2050 process), the search for life on exoplanets will be a priority in the next decades. Two concepts for direct imaging space missions are being developed for this purpose: the Habitable Worlds Observatory (HWO) and the Large Interferometer for Exoplanets (LIFE). These two concepts operate in different spectral regimes: HWO is focused on reflected light spectra in the ultraviolet, visible, and near-infrared (UV/VIS/NIR), while LIFE will operate in the mid-infrared (MIR) to capture the thermal emission of temperate exoplanets.

Aims. In this study, we aim to assess the potential of HWO and LIFE to characterize a cloud-free Earth twin orbiting a Sun-like star at a distance of 10 pc, both as separate missions and in synergy with each other. We aim to quantify the increase in information that can be gathered by joint atmospheric retrievals on a habitable planet.

Methods. We performed Bayesian retrievals on simulated data obtained by an HWO-like mission and a LIFE-like one separately, then jointly. We considered the baseline spectral resolutions currently assumed for these concepts and used two increasingly complex noise simulations, obtained using state-of-the-art noise simulators.

Results. An HWO-like concept would allow one to strongly constrain H2O, O2, and O3 in the atmosphere of a cloud-free Earth twin, while the atmospheric temperature profile is not well constrained (with an average uncertainty ≈100 K). LIFE-like observations would strongly constrain CO2, H2O, and O3 and provide stronger constraints on the thermal atmospheric structure and surface temperature (down to ≈10 K uncertainty). For all the investigated scenarios, both missions would provide an upper limit on CH4. A joint retrieval on HWO and LIFE data would accurately define the atmospheric thermal profile and planetary parameters. It would decisively constrain CO2, H2O, O2, and O3 and find weak constraints on CO and CH4. The significance of the detection is in all cases greater than or equal to the single-instrument retrievals.

Conclusions. Both missions provide specific information that is relevant for the characterization of a terrestrial habitable exoplanet, but the scientific yield can be maximized by considering synergistic studies of UV/VIS/NIR+MIR observations. The use of HWO and LIFE together will provide stronger constraints on biosignatures and life indicators, with the potential to be transformative for the search for life in the Universe.
KMT-2021-BLG-2609Lb and KMT-2022-BLG-0303Lb: Microlensing planets identified through signals produced by major-image perturbations
Authors: Han Cheongho , Albrow Michael D. , Lee Chung-Uk , Chung Sun-Ju , Gould Andrew , Hwang Kyu-Ha , Jung Youn Kil , Ryu Yoon-Hyun , Shvartzvald Yossi , Shin In-Gu , Yee Jennifer C. , Yang Hongjing , Zang Weicheng , Cha Sang-Mok , Kim Doeon , Kim Dong-Jin , Kim Seung-Lee , Lee Dong-Joo , Lee Yongseok , Park Byeong-Gon , Pogge Richard W.
Published: July 2024

Aims. We investigate microlensing data collected by the Korea Microlensing Telescope Network (KMTNet) survey during the 2021 and 2022 seasons to identify planetary lensing events displaying a consistent anomalous pattern. Our investigation reveals that the light curves of two lensing events, KMT-2021-BLG-2609 and KMT-2022-BLG-0303, exhibit a similar anomaly, in which short-term positive deviations appear on the sides of the low-magnification lensing light curves.

Methods. To unravel the nature of these anomalies, we meticulously analyze each of the lensing events. Our investigations reveal that these anomalies stem from a shared channel, wherein the source passed near the planetary caustic induced by a planet with projected separations from the host star exceeding the Einstein radius. We find that interpreting the anomaly of KMT-2021-BLG-2609 is complicated by the “inner–outer” degeneracy, whereas for KMT-2022-BLG-0303, there is no such issue despite similar lens-system configurations. In addition to this degeneracy, interpreting the anomaly in KMT-2021-BLG-2609 involves an additional degeneracy between a pair of solutions, in which the source partially envelops the caustic and the other three solutions in which the source fully envelopes the caustic. As in an earlier case of this so-called von Schlieffen–Cannae degeneracy, the former solutions have substantially higher mass ratio.

Results. Through Bayesian analyses conducted based on the measured lensing observables of the event time scale and angular Einstein radius, the host of KMT-2021-BLG-2609L is determined to be a low-mass star with a mass ~0.2 M⊙ in terms of a median posterior value, while the planet’s mass ranges from approximately 0.032 to 0.112 times that of Jupiter, depending on the solutions. For the planetary system KMT-2022-BLG-0303L, it features a planet with a mass of approximately 0.51 MJ and a host star with a mass of about 0.37 M⊙. In both cases, the lenses are most likely situated in the bulge.
Motivation and success factors in radiological research in Germany – results of a survey by the Methodology and Research Working Group of the German Radiological Society
Authors: Wegner Franz , Heinrichs Helen , Stahlmann Katharina , Molwitz Isabel , Keller-Yamamura Sarah , Kloeckner Roman , Barkhausen Jörg , Bäuerle Tobias , Cyran Clemens C , Dietzel Matthias , Eisenblätter Michel , Hilger Ingrid , Jung Caroline , Schick Fritz , Kiessling Fabian , Bannas Peter
Published: July 2024

Investigation of motivation and identification of success factors in radiology research in Germany.

Using a German online survey (54 questions, period: 3.5 months), demographic aspects, intrinsic and extrinsic success characteristics, as well as personal and organizational success factors were surveyed based on a career success model. The survey results were reported descriptively. The correlations between success factors and success characteristics were examined using linear, binary-logistic, and multinomial regression models.

176 people (164 academically active, 10 not academically active) answered the survey. Most participants (80%, 139/174) worked at a university hospital. 32% had privatdozent or professor as their highest academic title (56/173). The researchers' main motivation was intrinsic interest in research (55%, 89/163), followed by a desire to increase their own career opportunities (25%, 41/163). The following were identified as factors for intrinsic success: i) support from department management (estimate=β=0.26, p<0.001), ii) good work-life balance (β=0.37, p<0.001), and iii) the willingness to pursue science even after reaching the career goal (β=0.16, p<0.016). Relevant factors for extrinsic scientific success were mentoring, protected research time, and activities in professional societies.

Researchers in German radiology are mainly intrinsically motivated. Factors known from the literature that determine intrinsic and extrinsic scientific success were confirmed in this study. Knowledge of these factors allows targeted systematic support and could thus increase scientific success in German radiology.
Efficacy of Thyroid Hormone Replacement Therapy in Nasopharyngeal
Carcinoma Patients with Radiation-Induced Subclinical
Hypothyroidism
Authors: Lian Chen-Lu , Chen Gui-Ping , Zhou Rui , Yu Yi-Feng , Zhou Ping , Lin Qin , Wu San-Gang
Published: July 2024

Aims Hypothyroidism is a common side effect of radiotherapy for
nasopharyngeal carcinoma. However, the impact of thyroid hormone replacement
therapy on patients with radiation-induced subclinical hypothyroidism has not
been extensively explored. This study aimed to analyze the efficacy of thyroid
hormone replacement therapy in nasopharyngeal carcinoma patients with
subclinical hypothyroidism.

Methods Patients diagnosed with nasopharyngeal carcinoma who developed
subclinical hypothyroidism after definitive radiotherapy between September 2019
and December 2020 were selected for inclusion in this study. Prior to thyroid
hormone replacement therapy and after maintaining euthyroidism for 6–12 months
through thyroid hormone replacement therapy, assessments using the SF36 Brief
Health Status Scale and the Hypothyroidism-related Symptom Questionnaire were
conducted via trained questionnaires. Lipid profiles were assessed at baseline
and after 6–12 months of thyroid hormone replacement therapy. Statistical
analyses were performed using matched samples T-test or Mann-Whitney U test.

Results The median follow-up period was 14.5 months. The median score of
hypothyroid symptoms was 5.5 out of 19 points, with the most common symptoms
being chills (65.0%), fatigue (50.0%), weight gain (45.0%), and limb numbness
(40.0%). Thyroid hormone replacement therapy did not significantly improve the
quality of life, hypothyroidism-related symptoms, or blood lipid profile in
patients. However, there was an observed downward trend in serum cholesterol
levels following treatment (P=0.052).

Conclusion Thyroid hormone replacement therapy did not have a significant
impact on alleviating hypothyroid symptoms, improving quality of life, or
enhancing lipid profiles in patients with radiation-induced subclinical
hypothyroidism. Nevertheless, a potential decrease in serum cholesterol levels
was noted after thyroid hormone replacement therapy.
High- and Low-carb Diet and Fasting State Modify Alternative Maximal
Accumulated Oxygen Deficit
Authors: Firmino Matheus Simionato , Norberto Matheus S. , Putti Germano Marcolino , de Oliveira Carolina Lemos , da Silva Rumayor Bianka , Torini João Victor Gatto , Papoti Marcelo
Published: July 2024

This investigation aimed to assess whether the alternative method of estimating
the maximal accumulated oxygen deficit (MAODalt) can detect changes
in energy system contribution in different substrate availabilities. Following a
graded exercise test to determine maximal oxygen uptake intensity
(iVO2max), 26 recreational runners performed a time to exhaustion
effort (TTE) as baseline at 110% iVO2max. The same TTE was performed
in fasting state, then, a muscle glycogen depletion protocol was executed.
Subsequently, participants received a low-carbohydrate diet and beverages
containing high (H-CHO, 10.8±2.1 g·kg− 1), moderate (M-CHO,
5.6±1.1 g·kg− 1), or zero (Z-CHO, 0.24±0.05 g·kg− 1)
carbohydrates. Another TTE was performed 24 h later. Each energy system
contribution was assessed. Generalized linear mixed models were used for
statistical analysis (p<0.05). H-CHO increased relative anaerobic capacity
(slope effect [baseline –intervention]x[H-CHO – M-CHO]) due to the relative
lactic contribution maintenance (slope effect [baseline – intervention]x[H-CHO –
Z-CHO] or [H-CHO – M-CHO]) and increase in relative alactic contribution
(6.3±3.5 kJ·min− 1). The aerobic contribution was lower
(− 8.7±4.0 kJ·min− 1), decreasing performance (− 34±16 s) for
H-CHO. M-CHO and Z-CHO maintained anaerobic capacity due to increase in alactic
contribution (slope effect [fasting – intervention]x[M-CHO – H-CHO]; and Z-CHO
was 7.3±3.4 kJ·min− 1 higher than baseline). Fasting increased
relative alactic (2.9±1.7 kJ·min− 1) but decreased aerobic
contribution (− 3.3±2.3 kJ·min− 1), impairing performance
(− 17±12 s). In conclusion, MAODalt can detect changes in energy
system supply in different nutritional states. Therefore, participantʼs
nutritional state must be considered prior to conducting the test.
A Formal [3+3] Annulation of Morita–Baylis–Hillman Ketones to Construct Pyrimidobenzothiazoles
Authors: Easwar Srinivasan , Kumari Rajkiran , Kumawat Suman
Published: July 2024

A calcium triflate-promoted reaction of Morita–Baylis–Hillman (MBH) ketones, derived by the oxidation of MBH adducts, with 2-aminobenzothiazoles resulted in the formation of 4H-pyrimido[2,1-b]benzothiazoles. Formally, the transformation represents a [3+3] annulation and presumably proceeds via an aza-Michael addition followed by an intramolecular condensation. The reaction is completely regioselective and tolerates a wide range of substrates to afford a variety of analogues of the fused heterocycle in good yields.
Hypervalent Iodine Mediated Ring-Opening 1,3-Difluorination of Benzylidenecyclopropanes
Authors: Huang Long-Ling , Li Jia-Yi , Sun Qigang , Li Qingjiang , Zhao Gui-Yang , Wang Honggen
Published: July 2024

1,3-Difluorinated compounds are characterized by their unique conformation, influenced by 1,3-dipolar minimization effects. However, their synthetic methods are relatively limited. Here, a ring-opening 1,3-difluorination of benzylidenecyclopropanes (BCPs) using HF·Py, mediated by an electron-poor hypervalent iodine reagent, which is generated in situ by the oxidation of o-nitroiodobenzene with mCPBA is described. The protocol features mild reaction conditions, good functional group tolerance, and moderate to good yields. Additionally, the synthetic utility of this method is showcased by further transformations of the olefin group and allylic fluoride motif.
Intraplexal Aneurysm of the Distal Segment of the Anterior Choroidal Artery: A Case Report and Review of Literature
Authors: Abouelleil Mohamed , Nabulsi Omar , Hamidi Sabah , Aljiboori Karrar , Mazaris Paul , Singer Justin
Published: July 2024

Aneurysms of the anterior choroidal artery (AChA) are the most common pathology of the vessel. Although proximal aneurysms at the internal carotid artery (ICA) and AChA junction are common, their occurrence in the distal segment of the AChA is quite rare. We report a case of a distal AChA aneurysm occurring in the intraplexal segment of the AChA. To our knowledge, this is the first reported case of an intraplexal distal AChA aneurysm.
Die Auswirkung von Leistungskonzentration auf die Ergebnisqualität in
Geburtshilfeabteilungen – Eine empirische Analyse der Sterblichkeit von
Neugeborenen in deutschen Krankenhäusern
Authors: Kianpour Fabian
Published: July 2024

Die Auswirkung der Leistungskonzentration auf die Ergebnisqualität stationärer
Leistungen im Krankenhaussektor ist Gegenstand kontroverser wissenschaftlicher
Diskussionen. Besonders wichtig ist diese Debatte im Bereich der Geburtshilfe.
Ziel dieses Beitrags war es, den Einfluss von Volume-Outcome-Faktoren und
wettbewerbsökonomischen Parametern auf die Ergebnisqualität in geburtshilflichen
Abteilungen deutscher Krankenhäuser zu untersuchen. Diesem Zweck liegt ein
quantitativer Forschungsansatz zu Grunde, bei dem Struktur- und Leistungsdaten
von 412 deutschen Krankenhäusern im Jahr 2021 analysiert wurden. Zur Überprüfung
der Hypothesen wurde ein polynomiales multiples Regressionsmodell mit insgesamt
elf unabhängigen Variablen geschätzt. Als Indikator für die Ergebnisqualität in
Geburtshilfeabteilungen diente die Sterblichkeit von Neugeborenen. Entgegen den
Erwartungen spielen die für Geburten wichtigen wettbewerbsökonomischen Parameter
eine eher untergeordnete Rolle, während für Volume-Outcome-Beziehungen starke
empirische Belege gefunden werden konnten. Die Ergebnisse dieser Studie legen
nahe, dass positive Qualitätseffekte von Leistungskonzentrationen auch im
Bereich der Geburtshilfe überwiegen und liefern damit unterstützende Indizien
für die Argumentationslogik der bevorstehenden Krankenhausreform in
Deutschland.
Ende der Pandemie – Beginn der Digitalisierung im Öffentlichen
Gesundheitsdienst? Das nationale Förderprogramm Pakt-öGD
Authors: Yavuz Mesut , Savaskan Nicolai
Published: July 2024

Hintergrund Der datentechnisch desolate Zustand der Gesundheitsämter wurde
spätestens mit dem Eintreten der Covid-19-Pandemie öffentlich evident. Die
fehlende Interoperabilität und mangelnde Vernetzung der Gesundheitsämter
entwickelten sich schnell zu Blockaden in der Kontaktpersonennachverfolgung und
Pandemiebekämpfung.

Methodik Als Grundlage der Studie wurden Kennzahlen und Fördervolumina des
Pakt-ÖGD ausgewertet und mittels deskriptiver Parameter analysiert. Zusätzlich
wurde eine Literaturrecherche zum Pakt-ÖGD und verwandter Begriffe
durchgeführt.

Ergebnisse Der Pakt-ÖGD stellt die bisher größte Finanzierungsoffensive
für den ÖGD dar. Trotz Digitalisierungspakt und den ersten Mittelausschüttungen
besteht allerdings kein Konsens über die Digitalisierungsziele, wie den ISCODE,
Findability, Accessibility, Interoperability und Reuse (FAIR-Konzept). So
präsentiert das RKI aktuell ein neues Elektronisches Melde- und
Informationssystem für Gesundheitsämter (EMIGA), dass parallel zum DEMIS als
bundeseinheitliche Kernanwendung für den Infektionsschutz eingeführt werden
soll.

Schlussfolgerung In Analogie zur Health Literacy benötigt der ÖGD zur
Kompetenzstärkung eine Digital Literacy und konsentierte, gemeinsame Ziele, was
Digitalisierung als Prozess schaen soll. Für einen zukunftsfähigen öffentlichen
Gesundheitsdienst bedarf es eines offenen und anschlussfähigen Netzwerkes über
den Infektionsschutz (pandemic prevention, preparedness and response – PPPR)
hinaus hin zu einer digital nutzbaren globalen One-Health Plattform.
Enhancing Secure Messaging in Electronic Health Records: Evaluating the Impact of Emoji Chat Reactions on the Volume of Interruptive Notifications
Authors: Will John , Small William , Iturrate Eduardo , Testa Paul , Feldman Jonah
Published: July 2024

Background Electronic health record secure messaging (EHRSM) is an increasingly utilized tool for communication among clinicians. However, there is concern about the growing quantity of disruptions it presents via interruptive notification.

Objectives The primary aim of this study is to assess whether introducing emoji reactions, which do not trigger push notifications in EHRSM, can alleviate the burden of interruptive notifications. The second aim is to use messaging notification metadata to identify subgroups that might benefit from targeted interventions to aid the adoption of this innovation.

Methods We implemented the emoji reaction feature into EHRSM across a large academic health system. We evaluated the volume of push notifications 11 weeks before (pre-emoji period) and after (post-emoji period) introducing emoji reactions in EHRSM. Notification metadata was categorized by user type, and users were stratified based on notification volume.

Results There were 1,387,506 fewer push notifications in the post-emoji period (a decrease of 4.7%). Subgroups of users with increasing mean daily push notifications in the pre-emoji period were associated with decreasing mean daily push notifications in the post-emoji period. Among the eight user subgroups, six experienced a significant reduction in interruptive notifications, with the pharmacy and “other” subgroups not observing a reduction. Users in the top quartile of notification volume saw the greatest reduction in burden across each user subgroup.

Conclusion Integrating emoji reactions into EHRSM across a large academic health system significantly reduced the burden of push notifications among EHRSM users. Utilizing messaging notification metadata allowed us to identify subgroups that require additional intervention.
Outcome of Twins Discordant for Major Anomalies
Authors: Bhutia Tseten Zangmu , Kolar Geeta , Kavuri Kamala , Redishetty Saritha , Reddy Prathiba , Singh Arati , Pawar Smita , Kachakayala Mounika , Shivaramegowda Raksha , Vavilala Suseela
Published: July 2024

Objectives This article determines the incidence, management, and outcomes of twins discordant for major structural anomalies.

Materials and Methods A retrospective observational study was conducted from 2011 to 2021. Pregnant women discordant for major malformations as confirmed postnatally were included in the study. Demographic and clinical details were collected from medical records. Determining the incidence and profile of twins discordant for major structural anomalies and their management and outcomes were considered as primary objectives that were detailed in dichorionic (DC) and monochorionic (MC) twin pregnancies.

Results A total of 83 subjects were included, with an incidence of 1.76% in DC pregnancies and 1.4% in MC pregnancies. Major structural anomalies among DC twins were musculoskeletal (26%), followed by circulatory system anomalies (20.2%), while among MC twins, the majority were found to be central nervous system anomalies (35.7%). Gastrointestinal system anomalies were found the least, with 5.8% in DC anomalous twins, and none were observed in MC anomalous twins. Live birth rate among anomalous twins was found to be 79.71 and 64.29%, and in normal cotwins, it was 92.75 and 85.71% in DC and MC twins, respectively. Surviving anomalous twins underwent postnatal surgery or intervention in 25/69 (36.2%) DC twins, out of which 20 infants were alive and healthy. In the MC anomalous twin group, 3/14 (21.42%) underwent surgical correction; all were alive and well. Postnatally, babies were followed up until 2 years of life. The survival rate for anomalous twins was 47.82% in DC and 35.7% in MC twins. Normal cotwins had overall favorable outcomes, with a survival rate of 89.8 and 85.7% in DC and MC twins, respectively.

Conclusion In DC twins discordant for major anomalies, expectant management is a safe option.
Influence of width of squeeze film damper on the transient response of rotor systems
Authors: Yang Zhongyu , Li Jiaqi , Chen Jiali , Feng Yinli
Published: July 2024

The squeeze film damper (SFD) is a damping device that has been widely used in rotating machines. The SFD can effectively suppress rotor vibration and reduce transmitted forces. However, it would cause complex motions of the rotor system under specific operating conditions. This paper investigates the support structure of a high-pressure stage simulated rotor in an aircraft engine. A dynamic model of the SFD considering the effects of inertia and cavitation is established to investigate the influence of structural parameters on the stiffness and damping coefficient of the damper. Subsequently, a finite element model of the Jeffcott rotor–SFD system is developed to explore the effects of the structure parameters of the SFD on the critical speed, mode shapes, and other dynamic characteristics of the Jeffcott rotor–SFD system. Experimental tests are conducted to validate and refine the numerical calculations regarding the dynamic characteristics of the rotor–damper system. The results indicate that there is consistency between numerical simulations and experimental results. Within a certain range, enlarging the width of the damper can significantly increase the magnitude of the pressure distribution of the oil film. However, when the pressure amplitude increases to the saturation vapor pressure of the lubricating oil, the cavitation effect begins to manifest. As the width of the damper increases, both the stiffness coefficient and damping coefficient of the SFD are enhanced. Consequently, the vibration reduction effectiveness of the SFD is significantly improved.
Direct visualization of laser-driven dynamic fragmentation in tin by in situ x-ray diffraction
Authors: Yang Jing , Wang Xinxin , Xu Liang , Wang Qiannan , Sun Yi , Li Jiangtao , Zhang Lin , Li Yinghua , Yu Yuying , Wang Pei , Wu Qiang , Hu Jianbo
Published: July 2024

We present a novel method for investigating laser-driven dynamic fragmentation in tin using in situ X-ray diffraction. Our experimental results demonstrate the feasibility of the method for simultaneously identifying the phase and temperature of fragments through analysis of the diffraction pattern. Surprisingly, we observe a deviation from the widely accepted isentropic release assumption, with the temperature of the fragments being found to be more than 100 K higher than expected, owing to the release of plastic work during dynamic fragmentation. Our findings are further verified through extensive large-scale molecular dynamics simulations, in which strain energies are found to be transferred into thermal energies during the nucleation and growth of voids, leading to an increase in temperature. Our findings thus provide crucial insights into the impact-driven dynamic fragmentation phenomenon and reveal the significant influence of plastic work on material response during shock release.
Phase coherence—A time-localized approach to studying interactions
Authors: Barnes S. J. K. , Bjerkan J. , Clemson P. T. , Newman J. , Stefanovska A.
Published: July 2024

Coherence measures the similarity of progression of phases between oscillations or waves. When applied to multi-scale, nonstationary dynamics with time-varying amplitudes and frequencies, high values of coherence provide a useful indication of interactions, which might otherwise go unnoticed. However, the choice of analyzing coherence based on phases and amplitudes (amplitude-weighted phase coherence) vs only phases (phase coherence) has long been seen as arbitrary. Here, we review the concept of coherence and focus on time-localized methods of analysis, considering both phase coherence and amplitude-weighted phase coherence. We discuss the importance of using time-localized analysis and illustrate the methods and their practicalities on both numerically modeled and real time-series. The results show that phase coherence is more robust than amplitude-weighted phase coherence to both noise perturbations and movement artifacts. The results also have wider implications for the analysis of real data and the interpretation of physical systems.
Alfvén-fast wave coupling in a 3D non-uniform medium
Authors: Davies R. , Wright A. N.
Published: July 2024

In this paper, we consider the process of Alfvén-fast wave mode coupling, through numerical simulation. We model the process using the ideal, linear magnetohydrodynamic equations on a three-dimensional Cartesian grid; assuming the cold plasma limit, β≪1. We initialize the simulation with a cylindrical Alfvén wave pulse (comprising an azimuthal magnetic field and velocity perturbations) propagating along a uniform magnetic field. The wave starts in a region where the density is uniform. As it propagates, part of the Alfvén wave encounters a change in density, before emerging into a second uniform region. We introduce the natural Helmholtz Hodge decomposition as a method to identify the properties of the Alfvén wave perturbations at the end of the simulation. Our results show that the Alfvén wave propagates efficiently through the non-uniform region, with the wave pulse's final structure sharing strong characteristics of the initial wave pulse structure. More than 69% of the initial energy is carried by the transmitted Alfvén wave. Alfvén-fast wave coupling has potential applications in planetary magnetospheres, such as in the Io-Jupiter Alfvén wave interaction, and the solar corona.
Low-latency passive thermal desensitization of a silicon micro-ring resonator with self-heating
Authors: Lederman Joshua C. , Bilodeau Simon , Doris Eli , Blow Eric C. , Zhang Weipeng , Jimoh Yusuf , Shastri Bhavin J. , Prucnal Paul R.
Published: July 2024

Analog photonic information processing can be implemented with low chip area using wavelength-division multiplexed systems, which typically manipulate light using micro-ring resonators. Micro-rings are uniquely susceptible to thermal crosstalk, with negative system performance consequences if not addressed. Existing thermal sensitivity mitigation methods face drawbacks including high complexity, high latency, high digital and analog hardware requirements, and CMOS incompatibility. Here, we demonstrate a passive thermal desensitization mechanism for silicon micro-ring resonators exploiting self-heating resulting from optical absorption. We achieve a 49% reduction in thermal crosstalk sensitivity and 1 µs adaptation latency using a system with no specialized micro-ring engineering, no additional control hardware, and no additional calibration. Our theoretical model indicates the potential for significant further desensitization gains with optimized micro-ring designs. Self-heating desensitization can be combined with active thermal stabilization to achieve both responsiveness and accuracy or applied independently to thermally desensitize large photonic systems for signal processing or neural network inference.
Quantum confinement and energy filtering effect enhancing the thermoelectric power factor of InGaAs with buried ErAs nanoparticles
Authors: Meng Ting , Zhang Xiwen , Yao Jinshan , Zhang Weiwei , Zhong Hongmei , Zhu Hongda , Zhang Yiyuan , Zhang Hui , Zhang Peng , Lu Hong , Zhao Yang
Published: July 2024

Given the strong coupling relationship between the Seebeck coefficient and electrical conductivity, achieving a significant increase in the thermoelectric power factor (PF) remains a formidable challenge. Previous studies have demonstrated that the ErAs:InGaAs system has the potential to leverage the energy filtering (EF) effect to enhance the Seebeck coefficient while maintaining high electron concentrations. Here, we present a method that significantly enhances the thermoelectric PF of InGaAs through the dual effects of quantum confinement and EF effects. Density Functional Theory calculations further demonstrate that the alterations in the ErAs band structure induce the EF effect. The results show that the ErAs quantum dots:In0.53Ga0.47As composite films exhibit high electrical conductivity and high Seebeck coefficient in the intermediate temperature range, resulting in a fivefold increase in the PF at 515 K. Our research presents a prospective approach to leveraging the combined effects for the advancement of high-performance thermoelectric materials.
The motional Stark effect diagnostic for ITER
Authors: Foley E. L. , Levinton F. M. , Uzun-Kaymak I. U. , Galante M. E. , Zhang X.
Published: July 2024

An overview of the plans for the motional Stark effect (MSE) diagnostic installation on the International Thermonuclear Experimental Reactor (ITER) is presented. The MSE diagnostic uniquely provides spatially localized magnetic field measurements inside the plasma. These are used to constrain equilibrium reconstructions to determine q(r), the safety factor as a function of minor radius. Meeting the system requirements to deliver q-profiles and related quantities with the specified radial resolution of 20 points over the minor radius, 10 ms time resolution, and better than 10% accuracy is challenging. MSE systems observe the D/H-α emission near 656.3 nm from neutral beams. As the beam atoms traverse the magnetic field, B⃗, at high velocity, v⃗, they experience a Lorentz electric field, v⃗×B⃗, which causes the spectral emission to be split and polarized due to the Stark effect. Traditional MSE-LP (line polarization) measurements determine the direction of the magnetic field in the observation volume using polarimetric analysis of the detected light. The harsh conditions of ITER are expected to deposit thin films of contaminants on the first mirror, which would alter the polarization state of reflected light significantly. On ITER, the combination of high magnetic field strength and high energy beams makes the Stark spectrum resolution suitable for the determination of the magnetic field magnitude from the line shift, so this approach has been selected. Every aspect of the measurement system must be planned for the burning plasma environment and carefully analyzed ahead of time. Current status and plans for the system are presented.
Investigation on outlet boundary conditions in lattice Boltzmann simulations of flow boiling heat transfer
Authors: Wang Si-Cheng , Tong Zi-Xiang , He Ya-Ling , Li Dong , Du Shen
Published: July 2024

Pseudopotential lattice Boltzmann (LB) models have been applied to simulate flow boiling heat transfer in recent years. Outlet boundary condition is one of the main challenges to carry out the flow boiling LB simulations. In order to clarify the issues involved in the outlet boundary implementation for flow boiling simulations, the numerical performances of two LB outlet boundary schemes are investigated. One is the convective boundary scheme, and the other is the pressure boundary scheme. Numerical results show that the convective boundary does not control the pressure at the outlet, leading to the continuously rising of the system pressure, while the pressure boundary does not allow bubbles to flow out. Hence, a novel artificial condensation zone is designed before the pressure outlet boundary to avoid two-phase outflow. The effective artificial condensation of vapor is achieved by tuning the equation of state and the latent heat source term in the zone. By employing pressure boundary condition along with the novel artificial condensation zone, the pressure in flow boiling simulation is successfully controlled, and the two-phase flow can be simulated continuously. Finally, simulation of flow boiling in a microchannel is implemented using the proposed outlet boundary treatment. Flow regime transition from the bubbly flow to the slug flow is well captured.
Suggesting the high-pressure route to metastable high entropy alloys with ultra-large lattice distortions
Authors: Mukhamedov Boburjon , Alling Björn
Published: July 2024

One of the key features of high entropy alloys is their severe local lattice distortions, which can lead to beneficial and unusual combinations of mechanical properties. Most reported high entropy alloys (HEAs) are made of size- and chemically similar elements, but if including a component with a distinct size difference was possible, further increase in distortions could be foreseen. However, such additions have typically been disregarded as such alloys are thought to be unmixable. Here, we predict the possibility of mixing such large elements into well-studied HEAs with the help of high or moderate pressure. Miscibility of three large elements in two alloy systems has been studied: Mg/Zr addition in CoCrFeMnNi alloy and Pb addition in MoNbTaTiV alloy. These new compositions are metastable at ambient conditions but can be stabilized with high pressures and probably quenched to ambient with suitable temperature–pressure protocols. We predict that some of the promising candidates can be thermodynamically stabilized at 15–20 GPa, or even lower pressures at elevated temperatures. If synthesized and quenched to ambient conditions, these metastable HEAs would possess ultra-large lattice distortions.
Broadband high-efficiency meta-holography from all-dielectric quasi-continuous metasurfaces
Authors: Liu Kaifeng , Chen Qinmiao , Liu Yanlin , Song Shichao , Zhang Haimo , Shi Lintong , He Mengyao , Xiao Siqi , Xiao Shumin , Zhang Xiaohu
Published: July 2024

The compactness and particular optical design make metasurface a competitive candidate for holographic display and storage. Recently, the selection and optimization for the used metasurface structures and types have become research spots. Now the most researched and demonstrated meta-holograms are often based on discrete structures, which can achieve high efficiency but comparatively narrow working bandwidths or a wide wavelength range but low power efficiency. Therefore, contemporary meta-holograms struggle for realizing simultaneous broadband and high efficiency. In this paper, all-dielectric quasi-continuous metasurfaces composed of nanostrips are introduced to expand the operating bandwidth for high efficiency meta-holography. Benefiting from the associated Pancharatnam–Berry phase, the nanostrips with spatially orientation angles continuous changes can realize arbitrary phase modulation. For the first time, the average power efficiency of a meta-hologram is experimentally measured to be 56.63% over a broad wavelength band ranging from 500 to 1000 nm. In addition, based on this kind of all-dielectric quasi-continuous nanostrips, we also design and experimentally achieve multicolor three-dimensional (3D) holographic images. Actually, such all-dielectric quasi-continuous methodology proposed here can be used to design other functional meta-devices, including optical metalens, nanoprinting, and information encryption.
Simultaneously performing interlayer copper interconnecting and TSV filling in stacked chips at room temperature based on copper electroplating
Authors: Huang Mengru , Lu Linhong , Ran Jingyang , Yang Fashun , Ma Kui
Published: July 2024

In this work, we have developed a novel method for simultaneously performing interlayer copper interconnecting and Cu filling inside TSVs. It was applied to demonstrate two-layer stacked chips that process the development of interlayer copper interconnecting and Cu pillar filling in through-silicon vias (TSVs) by copper electroplating at room temperature (25 °C). In the two-layer stacked structure, a chip with TSVs was bonded with another chip without TSVs using a permanent bonding adhesive. After all micro-channels were immersed in the copper sulfate electroplating solution by vacuum pumping, copper electroplating made the interlayer copper interconnecting structures and the simultaneously filled copper pillars in TSVs a homogeneous three-dimensional (3D) interconnected structure and did not show original interfaces. Furthermore, no apparent gaps, air bubbles, or cracks were observed in the 3D copper interconnecting structure. The measured direct current resistance and the critical frequency at which the skin effect occurs of the formed 3D copper interconnected structure were very close to the theoretical value. The pure copper 3D interconnected structure without inner interfaces is very valuable for high-quality 3D integrated systems.
GHz-level repetition rate synchronously pumped diamond Raman laser based on bidirectional gain
Authors: Zhu Chengjie , Yang Xuezong , Liu Yuxuan , Li Muye , Sun Yuxiang , Fang Jiajie , Chen Dijun , Chen Weibiao , Feng Yan
Published: July 2024

In this paper, we demonstrate an ultrafast diamond Raman laser at 1240 nm with a pulse repetition rate of 956.62 MHz, a pulse duration of 39.5 ps, and an average power of up to 3.3 W based on synchronous pumping. The pump source is an electrical-pulse-modulated picosecond pulsed laser at 1064 nm with a repetition rate of 239.16 MHz and a pulse duration of 65.4 ps. A quadrupling repetition rate of the Raman pulse is achieved by synchronously amplifying both the forward and backward Raman pulses and the amplified Raman pulse undergoing two round trips in the resonator within one pump pulse period. The compression ratio of the pulse duration from the pump to the Raman is 1.66. This work offers a convenient and efficient method to significantly enhance the repetition rate of ultrafast crystalline Raman lasers and proves that a non-coherent ultrafast pump pulsed laser can be converted to a coherent mode-locked ultrafast Raman pulsed laser based on Raman conversion.
Numerical study of erosion characteristics in U-shaped elbow and slurry pump
Authors: Hong Shiming , Peng Guangjie , Chang Hao , Yu Dehui , Ji Guangchao , Ma Lie , Wang Zengqiang
Published: July 2024

Centrifugal slurry pumps and supporting combined piping systems (including U-shaped elbows and tees) are widely employed in deep-sea mining, the petrochemical industry, power metallurgy, and other industrial fields. The main aim of this research is to study the effects of conveying parameters and particle properties on the collision and erosion characteristics in a U-shaped elbow and the 100SHL4147 slurry pump. Investigation through the computational fluid dynamic–discrete element method is carried out on the collision mechanisms and erosion characteristics under different flow conditions. The collision and erosion characteristics are numerically investigated based on the analysis of frequency and erosion distribution. The results indicate that the erosion degree of non-spherical particles is more severe than that of spherical particles, while the collision frequency is the opposite in the U-shaped elbow. However, the collision and erosion of non-spherical particles are higher than those of spherical particles in the slurry pump. With the increase in the flow rate, the maximum collision frequency shows an upward trend, except for the shroud, and the maximum erosion rate of each wetted part increases. The area from the blade inlet to the one-third of the blade pressure surface is the main collision and erosion region, where the anti-wear performance should be strengthened.
Coupling competition and energy transfer between C=C and C–H vibration in the process of cascaded stimulated Raman scattering of benzene–methanol solution
Authors: Ren Panpan , Men Zhiwei , Wang Shenghan , Sun Chenglin
Published: July 2024

We introduced the coupling competition and energy transfer between the C=C and C–H vibration modes in the process of cascaded stimulated Raman scattering (SRS) of benzene and methanol mixtures. The results show that when the molar fraction of methanol is 0.9, the SRS process related to Raman activity can be simultaneously induced in different molecules, and the SRS gains involving a common pump pulse are coupled and compete. Two new peaks (992 + 2839) and (992 + 2945) cm−1 appeared, which are attributed to the energy transfer between the C=C ring vibration and the –CH3 stretching vibration. The interaction between adjacent vibrations can produce strong Raman scattering and achieve efficient wavelength conversion, which may provide a simple method for realizing multi-wavelength laser sources.
Collision of rare-gas atoms on helium nanodroplets: Theoretical evidence for an efficient coagulation of heavy rare-gas atoms
Authors: Fixot Brendan , Louaas Elsa , Bonhommeau David A.
Published: July 2024

The coagulation of rare-gas atoms (RG = Ne, Ar, Kr, Xe, and Rn) in helium nanodroplets (HNDs) composed of 1000 atoms is investigated by zero-point averaged dynamics where a He–He pseudopotential is used to make the droplet liquid with proper energies. This method reproduces the qualitative abundances of embedded Arn+1 structures obtained by Time-Dependent Density Functional Theory and Ring Polymer Molecular Dynamics for Ar + ArnHe1000 collisions at realistic projectile speeds and impact parameters. More generally, coagulation is found to be much more efficient for heavy rare-gases (Xe and Rn) than for light ones (Ne and Ar), a behavior mainly attributed to a slower energy dissipation of the projectile in the HND. When coagulation does not occur, the projectile maintains a speed of 10–30 m s−1 within the HND, but its velocity vector is rarely oriented toward the dopant, and the projectile roams in a limited region of the droplet. The structure of embedded RGn+1 clusters does not systematically match their gas-phase global minimum structure, and more than 30% of RGn–RG unbound structures are due to one He atom located in between the projectile and a dopant atom.