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Energy and blast performance of beryllium in a model thermobaric composition in comparison with aluminum and magnesium

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Defence Technology（防务技术） 2024年第6期36卷 13-19页

作者： thomas M.Klapotke Stanisław Cudziło Waldemar A.Trzcinski Jozef Paszula Energetic Materials Research Department of ChemistryUniversity of Munich(LMU)Butenandtstrasse 5-13(D)81377MunichGermany Military University of Technology Faculty of Advanced Technologies and ChemistrySylwester Kaliski Str.200-908WarsawPoland

A direct comparison is made between the effectiveness of Al,Mg,and Be powders as additional fuels in model thermobaric compositions containing 20%fuel,20%ammonium perchlorate,and 60%RDX(1,3,5-Trinitro-1,3,5-triazacyclohexane)passivated with *** determined calorimetric measurements of the heat of detonation,along with the overpressure histories in an explosion chamber filled with nitrogen,were used to determine the quasi-static pressure(QSP)under anaerobic *** measurements were also performed in a semi-closed bunker,and all blast wave parameters generated after the detonation of 500 g charges of the tested explosives were *** calorimetry results,QSP values,and blast wave parameters(pressure amplitude,specific and total impulses)clearly indicate that Be is much more effective as an additional fuel than either Al or Mg in both anaerobic post-detonation reactions as well as the subsequent aerobic *** heat of detonation of the RDXwax/AP/Be explosive mixture is over 40%and 50%higher than that of the mixture containing aluminum and magnesium instead of beryllium,***,the TNT equivalent of the Be-containing composition due to the overpressure in the nitrogen-filled explosion chamber is 1.66,while the equivalent calculated using an air shock wave-specific impulse at a distance of 2.5 m is equal to *** high values of these parameters confirm the high reactivity of beryllium in both the anaerobic and aerobic stages of the thermobaric explosion.

关键词： Thermobaric explosives Beryllium Heat of detonation Quasi-static overpressure Blast wave parameters

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Light correcting light with nonlinear optics

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Advanced Photonics 2024年第2期6卷 41-49页

作者： Sachleen Singh Bereneice Sephton Wagner Tavares Buono Vincenzo D'Ambrosio thomas Konrad Andrew Forbes University of the Witwatersrand School of Physics Università degli studi di Napoli “Federico Ⅱ” Dipartimento di Fisica “E.Pancini” University of Kwa Zulu-Natal School of Chemistry and Physics

Structured light, where complex optical fields are tailored in all their degrees of freedom, has become highly topical of late, advanced by a sophisticated toolkit comprising both linear and nonlinear *** undesired structure from light is far less developed, leveraging mostly on inverting the distortion,e.g., with adaptive optics or the inverse transmission matrix of a complex channel, both requiring that the distortion be fully characterized through appropriate measurement. We show that distortions in spatially structured light can be corrected through difference-frequency generation in a nonlinear crystal without any need for the distortion to be known. We demonstrate the versatility of our approach using a wide range of aberrations and structured light modes, including higher-order orbital angular momentum(OAM) beams,showing excellent recovery of the original undistorted field. To highlight the efficacy of this process, we deploy the system in a prepare-and-measure communications link with OAM, showing minimal cross talk even when the transmission channel is highly aberrated, and outline how the approach could be extended to alternative experimental modalities and nonlinear processes. Our demonstration of light-correcting light without the need for measurement opens an approach to measurement-free error correction for classical and quantum structured light, with direct applications in imaging, sensing, and communication.

关键词： phase conjugation aberration correction orbital angular momentum nonlinear optics

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BLE beacons for sample position estimation in a life science automation laboratory

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Transportation Safety and Environment 2024年第3期6卷 111-123页

作者： Haiping Wu Steffen Junginger thomas Roddelkopf Hui Liu Kerstin Thurow Institute of Artificial Intelligence&Robotics(IAIR) Key Laboratory of Traffic Safety on Track of Ministry of EducationSchool of Traffic and Transportation EngineeringCentral South UniversityChangsha 410075HunanChina Institute of Automation(IAT) University of Rostock18119 RostockGermany Center of Life Science Automation(celisca) University of Rostock18119 RostockGermany

Estimation of the sample position is essential for working process monitoring and management in the life science automation lab*** low-energy(BLE)beacons have the advantages of low price,small size and low energy consumption,which make them a promising solution for sample position estimation in the automated *** fingerprinting models have been proposed to achieve indoor localization with the received signal strength(RSS)***,most of the research depends on intensive beacon *** estimation,which depends entirely on one beacon,is more suitable for sample position estimation in large automated *** complexity of the life science automation laboratory environment brings challenges to the traditional path loss model(PLM),which is a widely used radio wave propagation model-based proximity estimation *** this paper,BLE sensing devices for sample position estimation are *** BLE beacon-based proximity estimation is discussed in the framework of machine learning,in which the support vector regression(SVR)is utilized to model the nonlinear relationship between the RSS data and distance,and the Kalman filter is utilized to decrease the RSS data *** experimental results over different environments indicate that the SVR outperforms the PLM significantly,and provides 1 m absolute errors for more than 95%of the testing *** Kalman filter brings benefits to stable distance *** from proximity-based sample position estimation,the proposed framework turned out to be effective in position estimation between parallel workbenches and position estimation on an automated workstation.

关键词： BLE beacon position estimation proximity estimation received signal strength(RSS) support vector regression(SVR) life science automation laboratory

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Health economics for intra-capsular hip fractures undertaking fixation

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World Journal of Orthopedics 2024年第1期15卷 30-38页

作者： Anatole Wiik thomas Ashdown Ian Holloway Department of Surgery Trauma and OrthopaedicsLondon North West University HealthcareLondon HA13UJUnited Kingdom Department of Surgery Trauma and OrthopaedicsLondon North West University HospitalLondon HA13UJUnited Kingdom

BACKGROUND Hip fracture is a common musculoskeletal injury in the elderly requiring surgery *** operative mainstay of intra-capsular hip fractures is arthroplasty with a smaller proportion for *** To determine the most beneficial method of fixation for patients with intracapsular hip *** A registered audit from 2012-2018 was conducted on all intra-capsular hip fractures treated with 2 commonly used fixation *** notes,electronic records and clinical codes for cost benefit were evaluated.A validated quality of life measure was collected at least 1 year after *** A total of 83 patients were identified with intra-capsular fractures undergoing fixation during the retrospective *** were 47 cannulated cancellous screw and 36 sliding hip screw fixations with the case mix comparable for age,gender,co-morbidities and fracture *** was no significant difference in blood loss,tip apex distance,radiation exposure,length of stay,radiological union time,collapse,avascular necrosis or re-operation between fixation *** regression analysis demonstrated displaced intracapsular hip fractures correlated significantly with an undesirable outcome conferring a relative odds ratio of *** were 9(19%)and 4(11%)patients respectively,who required *** was no significant difference in health resource group tariff and implant cost with comparable EQ-5D and visual CONCLUSION No significant advantage was identified with differing fixation type,but irrespective there were a high number of patients requiring *** was predicted by initial fracture displacement and patient *** may need to be carefully considered for health economics and patient benefit.

关键词： Hip fracture Fixation Patient reported outcome measure Cost

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Applying Machine Learning Approach to Explore Childhood Circumstances and Self-Rated Health in Old Age-China and the US,2020-2021

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China CDC weekly 2024年第11期6卷 213-218,I0008-I0013页

作者： Shutong Huo Derek Feng thomas M.Gill Xi Chen Department of Health Society&BehaviorPublic HealthUniversity of CaliforniaIrvineCAUSA Department of Statistics and Data Science Yale UniversityNew HavenCTUS Department of Internal Medicine Yale School of MedicineNew HavenCTUS Department of Health Policy and Management Yale School of Public HealthNew HavenCTUS Department of Economics Yale UniversityNew HavenCTUS.

Introduction:Childhood circumstances impact senior health,prompting the introduction of machine learning methods to assess their individual and collective contributions to senior ***:Using health and retirement study(HRS)and China Health and Retirement Longitudinal Study(CHARLS),we analyzed 2,434 American and 5,612 Chinese participants aged 60 and *** inference trees and forests were employed to estimate the influence of childhood circumstances on self-rated health(SRH).Results:The conventional method estimated higher inequality of opportunity(IOP)values in both China(0.039,accounting for 22.67%of the total Gini coefficient 0.172)and the US(0.067,accounting for 35.08%of the total Gini coefficient 0.191).In contrast,the conditional inference tree yielded lower estimates(China:0.022,accounting for 12.79%of 0.172;US:0.044,accounting for 23.04%of 0.191),as did the forest(China:0.035,accounting for 20.35%of 0.172;US:0.054,accounting for 28.27%of 0.191).Childhood health,financial status,and regional differences were key determinants of senior *** conditional inference forest consistently outperformed others in predictive accuracy,as demonstrated by lower out-of-sample mean squared error(MSE).Discussion:The findings emphasize the need for early-life interventions to promote health equity in aging *** learning showcases the potential in identifying contributing factors.

关键词： collective inequality estimates

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Does topical vancomycin prevent fracture-related infections in closed fractures undergoing open reduction and internal fixation?A randomised controlled trial

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Chinese Journal of Traumatology 2024年第2期27卷 71-76页

作者： Mohit Gandhi Gopisankar Balaji Jagdish Menon Ruben Raj thomas Department of Orthopaedics Jawaharlal Institute of Postgraduate Medical Education and ResearchPondicherryIndia Department of Preventive and Social Medicine Jawaharlal Institute of Postgraduate Medical Education and ResearchPondicherryIndia

Purpose:The role of topical vancomycin in fracture-related infection(FRI)is *** few studies have reported their efficacy in open and high-risk extremity *** study aimed to assess topical vancomycin's role in reducing FRI in closed fractures undergoing open surgical intervention with an ***:This prospective randomized cohort study was carried out between February 2021 to January *** with isolated closed fractures,who were planned for open reduction and internal fixation within 2 weeks from the time of injury were included for this *** data collected included age,gender,socioeconomic status,mechanism of injury,diagnosis,Tscherne classification,and time interval to take up for *** were randomized into the intervention and control groups using the block randomization *** control group received only systemic antibiotic prophylaxis,whereas the intervention group received topical application of vancomycin powder in the surgical wound alongside systemic antibiotic *** primary outcome measure was the incidence of FRI among these *** and radiological findings and culture reports(in cases with infection)were recorded during the post-operative period and at 6 weeks of *** relevant statistical calculations were done using STATA statistical/data analysis-parallel edition version 16.0(StataCorp LLC).The quantitative variables like age and duration of the surgery were assessed for normalcy by Shapiro-Wilk W *** independent samples t-test with equal variances was applied to the age ***'s exact test was used for the analysis of the primary outcome measure(presence of FRI following surgery),and"Risk of FRI"and"Risk difference"between the 2 groups was *** strength of the association between qualitative variables was assessed using the Fisher's exact and Chi-square tests,***:There were 88 patients included in this *** statistical si

关键词： Infections Antibiotics Vancomycin Fractures

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Entangled photon pair generation in an integrated SiC platform

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Light(Science & Applications) 2024年第6期13卷 1041-1046页

作者： Anouar Rahmouni Ruixuan Wang Jingwei Li Xiao Tang thomas Gerrits Oliver Slattery Qing Li Lijun Ma National Institute of Standards and Technology 100 Bureau DrGaithersburgMD20899USA Department of Electrical and Computer Engineering Carnegie Mellon UniversityPittsburghPA15213USA

Entanglement plays a vital role in quantum information *** to its unique material properties,silicon carbide recently emerged as a promising candidate for the scalable implementation of advanced quantum information processing *** date,however,only entanglement of nuclear spins has been reported in silicon carbide,while an entangled photon source,whether it is based on bulk or chip-scale technologies,has remained ***,we report the demonstration of an entangled photon source in an integrated silicon carbide platform for the first ***,strongly correlated photon pairs are efficiently generated at the telecom C-band wavelength through implementing spontaneous four-wave mixing in a compact microring resonator in the 4H-silicon-carbide-on-insulator *** maximum coincidence-to-accidental ratio exceeds 600 at a pump power of 0.17 mW,corresponding to a pair generation rate of(9±1)×103 pairs/***-time entanglement is created and verified for such signal-idler photon pairs,with the two-photon interference fringes exhibiting a visibility larger than 99%.The heralded single-photon properties are also measured,with the heralded g(2)(0)on the order of 10−3,demonstrating the SiC platform as a prospective fully integrated,complementary metal-oxide-semiconductor compatible single-photon source for quantum applications.

关键词： quantum coincidence mixing

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Rethinking Global Context in Crowd Counting

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Machine Intelligence Research 2024年第4期21卷 640-651页

作者： Guolei Sun Yun Liu thomas Probst Danda Pani Paudel Nikola Popovic Luc Van Gool Computer Vision Lab ETH ZurichZurich 8092Switzerland Institute for Infocomm Research A*STARSingapore 138632Singapore Magic Leap Zirich 8050Switzerland

This paper investigates the role of global context for crowd ***,a pure transformer is used to extract features with global information from overlapping image *** by classification,we add a context token to the input sequence,to facilitate information exchange with tokens corresponding to image patches throughout transformer *** to the fact that transformers do not explicitly model the tried-and-true channel-wise interactions,we propose a token-attention module(TAM)to recalibrate encoded features through channel-wise attention informed by the context *** that,it is adopted to predict the total person count of the image through regression-token module(RTM).Extensive experiments on various datasets,including ShanghaiTech,UCFQNRF,JHU-CROWD++and NWPU,demonstrate that the proposed context extraction techniques can significantly improve the performanceover the baselines.

关键词： Crowd counting vision transformer global context attention density map.

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Modelling of the elastoplastic behaviour of the bio-cemented soils using an extended Modified Cam Clay model

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2184-2197页

作者： Xuerui Wang Christian B.Silbermann thomas Nagel Udo Nackenhorst Institute of Mechanics and Computational Mechanics Leibniz UniversitätHannoverAppelstr.9aHannover30167Germany Gesellschaft für Anlagen-und Reaktorsicherheit(GRS)gGmbH Theodor-Heuss-Straße 4Braunschweig38122Germany Geotechnical Institute Technische Universität BergakademieFreibergGustav-Zeuner-Str.1Freiberg09599Germany

An elastoplastic constitutive model based on the Modified Cam Clay(MCC)model is developed to describe the mechanical behaviour of soils cemented via microbially induced calcite precipitation(MICP).It considers the increase of the elastic stiffness,the change of the yield surface due to MICP cementation and the degradation of calcium carbonate bonds during ***,to capture the typical contraction-dilation transition in MICP soils,the original volumetric hardening rule in the MCC model is modified to a combined deviatoric and volumetric hardening *** model could reproduce a series of drained triaxial tests on MICP-treated soils with different calcium carbonate ***,we carry out a parametric study and observe numerical instability in some *** combination with an analytical analysis,our numerical modelling has identified the benefits and limitations of using MCCbased models in the simulation of MICP-cemented soils,leading to suggestions for further model development.

关键词： Microbially induced calcite precipitation(MICP) Elastoplasticity Modified cam clay(MCC) OpenGeoSys MFront Contraction-dilation transition

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A simulation study on spatial and time resolution for a cost-effective positron emission particle tracking system

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Particuology 2024年第5期88卷 312-322页

作者： Josephine Oppotsch Matthias Steinke Miriam Fritsch Fritz-Herbert Heinsius thomas Held Nikoline Hilse Viktor Scherer Ulrich Wiedner Ruhr-Universität Bochum Institut für Experimentalphysik I44801 BochumGermany Ruhr-Universität Bochum Lehrstuhl für Energieanlagen und Energieprozesstechnik44801 BochumGermany

This work is the second part of a simulation study investigating the processing of densely packed and moving granular assemblies by positron emission particle tracking (PEPT).Since medical positron emission tomography (PET) scanners commonly used for PEPT are very expensive,a PET-like detector system based on cost-effective organic plastic scintillator bars is being developed and tested for its *** this context,the spatial resolution of a resting positron source,a source moving on a freely designed model path,and a particle motion given by a discrete element method (DEM) simulation is studied using Monte Carlo simulations and the software toolkit *** not only extended the simulation and reconstruction to a moving source but also significantly improved the spatial resolution compared to previous work by adding oversampling and iteration to the reconstruction ***,in the case of a source following a trajectory developed from DEM simulations,a very good resolution of about 1 mm in all three directions and an average 3D deviation between simulated and reconstructed events of 2.3 mm could be ***,the resolution for realistic particle motion within the generic grate system (which is the test rig for further experimental studies) is well below the smallest particle *** simulation of the dependence of the reconstruction accuracy on tracer particle location revealed a nearly constant efficiency within the entire detector system,which demonstrates that boundary effects can be neglected.

关键词： Positron emission particle tracking Monte Carlo method Time-of-flight Plastic scintillators Silicon photomultipliers(SiPMs)

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