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A LN2-based cooling system for a next-generation liquid xenon dark matter detector

Nuclear Science and Techniques 2020年第8期31卷 24-34页

作者： Karl ludwig Giboni Pratibha Juyal Elena Aprile Yun Zhang Junji Naganoma INPAC and School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Laboratory for Particle and Cosmology Shanghai 200240China Columbia Astrophysics Lab and Physics department Columbia UniversityNew YorkNY 10027USA department of Physics and Astronomy Rice UniversityHoustonTX 77005USA

In recent years, cooling technology for liquid xenon(LXe) detectors has advanced driven by the development of dark matter(dM) detectors with target mass in the 100–1000 kg range. The next generation of dM detectors based on LXe will be in the 50,000 kg(50 t)range requiring more than 1 k W of cooling power. Most of the prior cooling methods become impractical at this *** cooling a 50 t scale LXe detector, a method is proposed in which liquid nitrogen(LN2) in a small local reservoir cools the xenon gas via a cold finger. The cold finger incorporates a heating unit to provide temperature regulation. The proposed cooling method is simple, reliable, and suitable for the required long-term operation for a rare event search. The device can be easily integrated into present cooling systems, for example the ‘‘Cooling Bus’ ’employed for the Panda X I and II experiments. It is still possible to cool indirectly with no part of the cooling or temperature control system getting in direct contact with the clean xenon in the detector. Also, the cooling device can be mounted at a large distance, i.e., the detector is cooled remotely from a distance of 5–10 m. The method was tested in a laboratory setup at Columbia University to carry out different measurements with a small LXe detector and behaved exactly as predicted.

关键词： Noble liquid detectors(scintillation,ionization,double-phase) dark matter detectors(WIMPs,axions,etc.) Large detector systems for particle and astroparticle physics Very low-energy charged particle detectors Time projection chambers Cryogenics detector cooling and thermo-stabilization

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Modeling West Nile Virus transmission in birds and humans:Advantages of using a cellular automata approach

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Infectious disease Modelling 2024年第1期9卷 278-297页

作者： Baki Cissé david r.Lapen K.Chalvet-Monfray Nicholas H.Ogden Antoinette ludwig Public Health Sciences division National Microbiology LaboratoryPublic Health Agency of CanadaSt-HyacintheCanada Groupe de recherche enÉpidémiologie des Zoonoses et SantéPublique(GrEZOSP) Facultéde Médecine VétérinaireUniversitéde MontréalSaint-HyacintheQuébecCanada Ottawa research and development Centre Science and Technology BranchAgriculture and Agri-Food CanadaOttawaK1A 0C6Canada Universitéde Lyon INRAEVetAgro SupUMR EPIAMarcy l’EtoileFrance UniversitéClermont Auvergne INRAEVetAgro SupUMR EPIASaint-Genès-ChampanelleFrance

In Canada,the periodic circulation of West Nile Virus(WNV)is difficult to predict and,beyond climatic factors,appears to be related to the migratory movements of infected birds from the southern United *** hypothesis has not yet been explored in a spatially distributed *** main objective of this work was to develop a spatially explicit dynamic model for the transmission of WNV in Canada,that allows us to explore non-climate related hypotheses associated with WNV transmission.A Cellular Automata(CA)approach for multiple hosts(birds and humans)is used for a test region in eastern Ontario,*** tool is designed to explore the role of host and vector spatial heterogeneity,host migration,and vector feeding *** developed a spatialized compartmental SEIrdS-SEI model for WNV transmission with a study region divided into 4 rectangular *** used 2010–2021 bird data from the eBird project and 2010–2019 mosquito data collected by Ontario Public Health to mimic bird and mosquito seasonal *** considered heterogeneous bird densities(high and low suitability areas)and homogeneous mosquito and human *** high suitability areas for birds,we identified 5 entry points for WNV-infected *** compared our simulations with pools of WNV-infected field collected *** and sensitivity analyses were performed using MATLAB *** results showed good correspondence between simulated and observed epidemics,supporting the validity of our model assumptions and *** analysis showed that a 5%increase or decrease in each parameter of our model except for the biting rate of bird by mosquito(c^(B,M)and mosquito natural mortality rate(d^(M)),had a very limited effect on the total number of cases(newly infected birds and humans),prevalence peak,or date of *** demonstrate the utility of the CA approach for studying WNV transmission in a heterogeneous landscape with multiple hosts.

关键词： Cellular automata Mosquito-borne diseases SEIrdS-SEI modeling West Nile Virus

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On proportional scintillation in very large liquid xenon detectors

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Nuclear Science and Techniques 2020年第9期31卷 90-97页

作者： Pratibha Juyal Karl-ludwig Giboni Xiang-dong Ji Jiang-Lai Liu School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai Key Laboratory for Particle Physics and Cosmology(INPAC)800 Dongchuan RoadShanghai 200240China

The charge readout of a liquid xenon(LXe)detector via proportional scintillation in the liquid phase was first realized by the Waseda group 40 years ago,but the technical challenges involved were *** the tests were successful,this method was finally discarded and eventually nearly ***,this approach is not considered for large LXe dark matter ***,the dual-phase technology was selected despite many limitations and *** two independent studies,two groups from Columbia University and Shanghai Jiao Tong University reevaluated proportional scintillation in the liquid *** studies established the merits for very large LXe detectors,but the Columbia group also encountered apparent limitations,namely the shadowing of the light by the anode wires,and a dependence of the pulse shape on the drift path of the electrons in the anode *** differences between the two studies,however,are not intrinsic to the technique,but a direct consequence of the chosen *** the geometrical differences into account,the results match without *** also agree with the original results from the Waseda group.

关键词： Liquid detectors Time projection chambers(TPC) Multiplication and electroluminescence in rare gases and liquids

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Effects of symmetric and asymmetric salt conditions on a selective solid-state nanopore assay

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Nano research 2022年第11期15卷 9936-9942页

作者： Ian d.Wadsworth Adam r.Hall Virginia Tech-Wake Forest University School of Biomedical Engineering and Sciences Wake Forest School of MedicineWinston-SalemNC 27101USA Comprehensive Cancer Center Wake Forest School of MedicineWinston-SalemNC 27157USA

Conventional solid-state nanopore measurements sense all translocating entities,necessitating meticulous analysis to differentiate target *** address this,we have established a selective assay with the platform that has shown utility in quantifying several nucleic acid ***,limited detection efficiency and intrinsic noise have so far limited assay resolution to 10 *** in this value require manipulation of translocation ***,we report the effects of NaCl conditions on assay *** first investigate symmetric conditions,finding sensitivity increases with salt concentration but selectivity is maximized at 1.0 M *** then probe asymmetric conditions,showing a remarkable impact on assay sensitivity and selectivity when measurement buffer NaCl concentration in the reservoir with the translocating molecules is low and the opposite reservoir is *** optimum conditions,we demonstrate detection of target biomolecules down to a concentration of 100 pM which is an improvement of 2 orders of magnitude over past results.

关键词： solid-state nanopores biomarkers amplification-free detection salt gradient nucleic acids

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deep learning for visualization and novelty detection in large X-ray diffraction datasets

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npj Computational Materials 2021年第1期7卷 942-947页

作者： Lars Banko Phillip M.Maffettone dennis Naujoks daniel Olds Alfred ludwig Materials discovery and Interfaces Institute for MaterialsRuhr University BochumBochumGermany National Synchrotron Light Source II Brookhaven National LaboratoryUptonNYUSA ZGH Center for Interface-Dominated High Performance MaterialsRuhr University BochumBochumGermany

We apply variational autoencoders(VAE)to X-ray diffraction(Xrd)data analysis on both simulated and experimental thin-film *** show that crystal structure representations learned by a VAE reveal latent information,such as the structural similarity of textured diffraction *** other artificial intelligence(AI)agents are effective at classifying Xrd data into known phases,a similarly conditioned VAE is uniquely effective at knowing what it doesn’t know:it can rapidly identify data outside the distribution it was trained on,such as novel phases and *** capabilities demonstrate that a VAE is a valuable AI agent for aiding materials discovery and understanding Xrd measurements both‘on-the-fly’and during post hoc analysis.

关键词： VAE uniquely latent

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Lattice thermal conduction in cadmium arsenide

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Chinese Physics B 2022年第11期31卷 424-430页

作者： r F Chinnappagoudra M d Kamatagi N r Patil N S Sankeshwar department of Physics S.S.Government First Grade CollegeNargund-582207KarnatakaIndia research resource Centre Visvesvaraya Technological UniversityBelagavi-590018KarnatakIndia department of Physics B V B College of Engineering and TechnologyHubliKarnataka 80031India department of Physics&Electronics CHRIST(Deemed to be University)Bangalore-560029KarnatakaIndia

Lattice thermal conductivity(LTC)of cadmium arsenide(Cd_(3)As_(2))is studied over a wide temperature range(1–400 K)by employing the Callaway *** acoustic phonons are considered to be the major carriers of heat and to be scattered by the sample boundaries,disorder,impurities,and other phonons via both Umklapp and normal phonon *** calculations of LTC of Cd_(3)As_(2)bring out the relative importance of the scattering *** systematic analysis of recent experimental data on thermal conductivity(TC)of Cd_(3)As_(2)samples of different groups,presented in terms of LTC,κL,using a nonlinear regression method,reveals good fits to the TC data of the samples considered for Td suggests a value of 0.2 for the Gruneisen *** is,however,found that for T>100 K the inclusion of the electronic component of TC,κe,incorporating contributions from relevant electron scattering mechanisms,is needed to obtain good agreement with the TC data over the wide temperature *** detailed investigations of TC of Cd_(3)As_(2)are required to better understand its suitability in thermoelectric and thermal management devices.

关键词： dirac semimetals Cd_(3)As_(2) thermal conductivity phonon scattering

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region-Aware Trace Signal Selection Using Machine Learning Technique for Silicon Validation and debug

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Computer Modeling in Engineering & Sciences 2019年第7期120卷 25-43页

作者： r.Agalya r.Muthaiah d.Muralidharan Junior research Fellow School of ComputingSASTRA Deemed UniversityThirumalaisamudramThanjavur-613401TamilnaduIndia Associate dean School of ComputingSASTRA Deemed UniversityThirumalaisamudramThanjavur-613401TamilnaduIndia Assistant Professor School of ComputingSASTRA Deemed UniversityThirumalaisamudramThanjavur-613401TamilnaduIndia

In today’s modern design technology,post-silicon validation is an expensive and composite *** major challenge involved in this method is that it has limited observability and controllability of internal *** will be an issue during execution how to address the useful set of signals and store it in the on-chip trace *** existing approaches are restricted to particular debug set-up where all the components have equivalent prominence at all the ***,the verification engineers will emphasis only on useful functional regions or *** to some constraints like clock gating,some of the regions can be ignored during ***,some of these regions can be verified deeply and have minimum errors compared to other control *** proposed system focusses on random signals that identify more errors which are prone to signal selection technique with low area *** enhance the observability,a machine learning technique is *** on the training samples of smaller designs,a model is developed to find out the contiguous neighbours of each *** can eliminate the obstacles of unknown *** system demonstrates using Opencores and ISCAS’89 benchmark circuits that result in easy and fast error detection compared to the state-of-theart of other *** is also verified using gate-level error models by cross-validation of each debug run.

关键词： Controllability error propagation machine learning observability signal selection

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Annual-perennial plant relationships and species selection for desert restoration

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Journal of Arid Land 2013年第3期5卷 298-309页

作者： Scott r ABELLA Stanley d SMITH department of Environmental and Occupational Health University of Nevada Las VegasLas VegasNevada 89154-3064USA School of Life Sciences University of Nevada Las VegasLas VegasNevada 89154-4004USA

Exotic plant invasion is a growing concern in the conservation and management of indigenous arid land ecosystems. By creating areas of ameliorated microclimates and fertile soil below their canopies, perennial plants might influence exotic annual plant invasions. We conducted a quantitative literature review of studies that compared exotic annual plant abundance among native perennial plant species and interspace （open areas） microsites in North America＇s Mojave desert, where exotic plant invasion has corresponded with increasing extent of wildfire and broad-scale ecosystem transformation. Ten studies compared exotic annual plant abundance between inter- spaces and below a total of 36 native perennial species. These studies revealed that：（1） With few exceptions, most native perennial species supported a greater abundance of exotic annuals than interspaces, indicating overall facilitation of exotic species by native perennials. （2） Exotic species abundance varied by orders of magnitude among native perennial species, with some perennial species harboring amounts of exotics similar to interspaces. （3） distributions of dominant exotic species varied, where Bromus rubens displayed a greater affinity for below-perennial microsites than did Schismus spp. and Erodium cicutarium that often were most abundant in interspaces. results suggest that the degree of facilitation of exotic plants warrants consideration when selecting native perennial species for revegetation and restoration projects.

关键词： Bromus rubens exotic fertile island invasive nurse plant positive plant interaction Schismus

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A COMBINATOrIAL APPrOACH TO THE OXIdATION rESISTANCE OF (Ti,Al)N ANd Ti-Al-Si-N HArd COATINGS

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Acta Metallurgica Sinica(English Letters) 2002年第1期15卷 6-14页

作者： r. Cremer d. Neuschutz Lehrshl für Theoretische Hüttenkunde Rheinisch-Westfalische Technische Hochschule Aachen 52056 AachenGermany

The increasing complexity of modern functional materials leads to the demandof a cost efficient tool for the development of new products. One possible approach to this questionis the adaptation of combinatorial methods to the specific requirements of materials *** methods, originally developed for the pharmaceutical industry, have recently been applied tothe screening of superconductive, magnetoresistant and photoluminescent materials. The principle ofthese combinatorial approaches is the deposition of large materials libraries in one processcombined with fast methods for the determination of the resulting properties. In this paper, thedeposition and characterization of laterally graded materials libraries (composition spread) ispresented. The films have been deposited by reactive magnetron sputtering, using two or threemetallic targets at a low angle to the substrate surface as well as a system of apertures. Toillustrate the advantages of combinatorial approaches for the development of advanced materials, themulticomponent metastable hardcoatings (Ti,Al)N and Ti-Al-Si-N are discussed with special emphasison the relations between structure and composition on the one hand and the oxidation resistance ofthese coatings on the other. The results illustrate that the composition spread approach is apowerful and cost efficient tool for the development and optimization of new multicomponentfunctional materials.

关键词： combinatorial chemistry hard coating PVd magnetron sputtering

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Skin Melanoma Classification System Using deep Learning

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Computers, Materials & Continua 2021年第7期68卷 1147-1160页

作者： r.Thamizhamuthu d.Manjula department of Computer Science and Engineering CEG CampusAnna UniversityChennaiIndia

The deadliest type of skin cancer is malignant *** diagnosis requires at the earliest to reduce the mortality *** this study,an efficient Skin Melanoma Classification(SMC)system is presented using dermoscopic images as a non-invasive *** SMC system consists of four modules;segmentation,feature extraction,feature reduction and finally *** the first module,k-means clustering is applied to cluster the colour information of dermoscopic *** second module extracts meaningful and useful descriptors based on the statistics of local property,parameters of Generalized Autoregressive Conditional Heteroscedasticity(GArCH)model of wavelet and spatial patterns by dominant rotated Local Binary Pattern(drLBP).The third module reduces the features by the t-test,and the last module uses deep learning for the *** individual performance shows that GArCH parameters of 3rd dWT level sub-bands provide 92.50%accuracy than local properties(77.5%)and drLBP(88%)based features for the 1st stage(normal/abnormal).For the 2nd stage(benign/malignant),it is 95.83%(GrACH),90%(drLBP)and 80.8%(Local Properties).The selected 2%of features from the combination gives 99.5%and 100%for 1st and 2nd stage of the SMC *** greatest degree of success is achieved on PH2 database images using two stages of deep *** can be used as a pre-screening tool as it provides 100%accuracy for melanoma cases.

关键词： dermoscopic images skin cancer melanoma deep learning autoregressive models

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