bluuebunny/crossref_metadata_2025 huggingface dataset:
Is It Possible to Perform Fifth Carpometacarpal Joint Arthroscopy? Cadaveric Study on Its Feasibility, Safety, and Potential Hazards in Portal Creation
Authors: Koo Siu Cheong Jeffrey Justin , Pang Henry , Ho Pak Cheong
Published: January 2022

Background Fifth carpometacarpal joint (CMCJ) fracture dislocation is a relatively rare injury and most will require operative treatment because of its unstable nature. Improper reduction and fixation lead to joint surface destruction, pain, and reduced grasping power. Intra-articular fragment reduction is often obscured by dorsally displaced ulnar fragment. Therefore, fifth CMCJ arthroscopy can be advantageous in assisting intra-articular fragment reduction. However, there is no detailed description of the portal landmarks or portals' relationship with adjacent important structures in the literature.

Purposes To explore the feasibility and safety of fifth CMCJ arthroscopy, locations of the portals are examined in cadaveric hand specimens. Their proximity to important anatomical structures such as dorsal cutaneous branch of ulnar nerve (DCBUN), ring finger and little finger extensor digitorum communis (EDC), and extensor digiti minimi (EDM) is measured.

Methods Fifth CMCJ arthroscopy is performed on 11 cadaveric hand specimens by specialist-level surgeon. The portals are marked and portal positions are further confirmed under the fluoroscopy. Then the cadaveric specimens were undergone anatomical dissection by specialist-level surgeon. During dissection, the spatial relationship between the portal positions and DCBUN, EDC to ring finger and little finger, and EDM is identified. The distance between the portals and the above important structures was measured in millimeters.

Results DCBUN was consistently found between fourth metacarpohamate (4-MH) and fifth metacarpohamate (5-MH) portals, with it being closer to the latter (mean distance, 2.03 mm; range, 0–4.43 mm; standard deviation [SD], 1.09 mm). The closest tendon for 4-MH portal is ring finger EDC (mean distance, 2.65 mm; range, 0–5.89 mm; SD, 1.78 mm), while 5-MH portal and accessory portal were closest to EDC (mean distance, 1.88 mm; range, 0–3.69 mm; SD, 1.25 mm) and EDM (mean distance, 7.79 mm; range, 6.63–10.72 mm; SD, 1.49 mm), respectively. During the process of specimen dissection, we found no damage to the above structures after portal introduction.

Conclusion The above findings support the use of fifth CMCJ arthroscopy, which can be used for assisted reduction in fifth metacarpal base fracture dislocation and hamate body fracture. Gentle soft tissue spreading technique during portal creation prevents injury to the important structure surrounding the portals.

Level of evidence This is a Level V study.
Ambiguous and Incomplete: Natural Language Processing Reveals Problematic Reporting Styles in Thyroid Ultrasound Reports
Authors: Dedhia Priya H. , Chen Kallie , Song Yiqiang , LaRose Eric , Imbus Joseph R. , Peissig Peggy L. , Mendonca Eneida A. , Schneider David F.
Published: January 2022

Objective Natural language processing (NLP) systems convert unstructured text into analyzable data. Here, we describe the performance measures of NLP to capture granular details on nodules from thyroid ultrasound (US) reports and reveal critical issues with reporting language.

Methods We iteratively developed NLP tools using clinical Text Analysis and Knowledge Extraction System (cTAKES) and thyroid US reports from 2007 to 2013. We incorporated nine nodule features for NLP extraction. Next, we evaluated the precision, recall, and accuracy of our NLP tools using a separate set of US reports from an academic medical center (A) and a regional health care system (B) during the same period. Two physicians manually annotated each test-set report. A third physician then adjudicated discrepancies. The adjudicated “gold standard” was then used to evaluate NLP performance on the test-set.

Results A total of 243 thyroid US reports contained 6,405 data elements. Inter-annotator agreement for all elements was 91.3%. Compared with the gold standard, overall recall of the NLP tool was 90%. NLP recall for thyroid lobe or isthmus characteristics was: laterality 96% and size 95%. NLP accuracy for nodule characteristics was: laterality 92%, size 92%, calcifications 76%, vascularity 65%, echogenicity 62%, contents 76%, and borders 40%. NLP recall for presence or absence of lymphadenopathy was 61%. Reporting style accounted for 18% errors. For example, the word “heterogeneous” interchangeably referred to nodule contents or echogenicity. While nodule dimensions and laterality were often described, US reports only described contents, echogenicity, vascularity, calcifications, borders, and lymphadenopathy, 46, 41, 17, 15, 9, and 41% of the time, respectively. Most nodule characteristics were equally likely to be described at hospital A compared with hospital B.

Conclusions NLP can automate extraction of critical information from thyroid US reports. However, ambiguous and incomplete reporting language hinders performance of NLP systems regardless of institutional setting. Standardized or synoptic thyroid US reports could improve NLP performance.
Echoes of Empire: racism and historical amnesia in the British media coverage of migration
Authors: Połońska-Kimunguyi Ewa
Published: January 2022

This paper looks at how the British media addressed the issue of migration in Europe between 2015 and 2018, four years when the topic was high on news and political agendas, due to the so-called ‘refugee crisis’ and the UK’s debate on Britain’s relationship with the European Union and free movement of people. Based on a sample of 400 articles from two national newspapers, The Guardian and The Times, the paper compares the content and discourse between the left-wing and right-wing press. The paper argues that media representations turn refugees into ‘migrants’ and portray them as either a threat to the national economy and security or as passive victims of distant circumstances. The study historicizes these media narratives and reveals that the discourse they employ advances the racialised mix of knowledge and historical amnesia and reproduces the age-old hierarchies of the colonial system which divided humans into superior and inferior species. Migrant voice is largely missing from the coverage. History, that could explain the causes of ‘migration’, the distant conflicts and Britain’s role in them, is also nowhere to be found. The paper considers the exclusion of history and migrant voices from stories told to the British audience and reflects on their domestic and international implications.
Coulomb blockade: Toward charge control of self-assembled GaN quantum dots at room temperature
Authors: Sgroi C. A. , Brault J. , Duboz J.-Y. , Chenot S. , Vennéguès P. , Ludwig A. , Wieck A. D.
Published: January 2022

We present capacitance–voltage [C(V)] measurements of self-assembled wurtzite-GaN quantum dots (QDs). The QDs are embedded in a charge-tunable diode structure and were grown by molecular beam epitaxy in the Stranski–Krastanov growth method. The internal electric fields present in GaN and its alloys together with its wide bandgap make this material system an ideal candidate for high-temperature quantum applications. Charges and the internal electric fields influence the energy spacing in the QDs. We correlate photoluminescence measurements with C(V) measurements and show single-electron charging of the QDs and a Coulomb blockade energy of around 60 meV at room temperature. This finding demonstrates the possibility of quantum applications at room temperature.
Enhanced electrical conductivity in graphene–copper multilayer composite
Authors: Pan Chaochao , Gaur Anand P. S. , Lynn Matthew , Olson Madison P. , Ouyang Gaoyuan , Cui Jun
Published: January 2022

For many years, researchers have been trying to make a material more conductive than silver by incorporating carbon nanotubes or graphene into copper to form a composite material. However, after a decade-long effort, only a few groups reported successful results, raising concerns about the feasibility of this composite approach. Here, we report our effort to validate the multilayer graphene–copper composite approach for improving electrical conductivity. We demonstrate that, with an estimated 0.008 vol. % graphene addition, copper’s electrical conductivity was improved to 104.2% of International Annealed Copper Standard (IACS) at room temperature. If the copper substrate used to make the multilayer composite is discounted using the parallel resistance model, the conductivity is calculated to be 185% IACS. This result could be further improved if the thickness of the copper layers can be further reduced.
Equation of state-driven radiative models for simulation of lightning strikes
Authors: Apsley M. , Millmore S. T. , Nikiforakis N.
Published: January 2022

This work is concerned with the numerical simulation of plasma arc interaction with aerospace substrates under conditions akin to lightning strike and in particular with the accurate calculation of radiative heat losses. These are important because they have a direct effect on the calculation of thermal and pressure loads on the substrates, which can lead to material damage under certain conditions. Direct numerical solution of the radiation transport equation (RTE) in mesoscale simulations is not viable due to its computational cost, so for practical applications reduced models are usually employed. To this end, four approximations for solving the RTE are considered in this work, ranging from a simple local thermodynamical behavior consideration, to a more complex spectral absorption dependent on the arc geometry. Their performance is initially tested on a one-dimensional cylindrical arc, before implementing them in a multi-dimensional magnetohydrodynamics code. Results indicate that inclusion of spectral absorption is necessary in order to obtain consistent results. However, the approaches accounting for the arc geometry require repeated solution of the computationally intensive Helmholtz equations, making them prohibitive for multi-dimensional simulations. As an alternative, a method using the net emission coefficient is employed, which provides a balance between computational efficiency and accuracy, as shown by comparisons against experimental measurements for a plasma arc attaching to an aluminum substrate.
Modeling energy transfer and absorption spectra in layered metal–organic frameworks based on a Frenkel–Holstein Hamiltonian
Authors: Dell’Angelo David , Momeni Mohammad R. , Pearson Shaina , Shakib Farnaz A.
Published: January 2022

Optimizing energy and charge transfer is key in design and implementation of efficient layered conductive metal–organic frameworks (MOFs) for practical applications. In this work, for the first time, we investigate the role of both long-range excitonic and short-range charge transfer coupling as well as their dependency on reorganization energy on through-space charge transfer in layered MOFs. A π-stacked model system is built based on the archetypal Ni3(HITP)2, HITP = 2,3,6,7,10,11-hexaiminotriphenylene, layered MOF, and a Frenkel/charge transfer Holstein Hamiltonian is developed that takes into account both electronic coupling and intramolecular vibrations. The dependency of the long- and short-range couplings of secondary building units (SBUs) on the stacking geometry is evaluated, which predicts that photophysical properties of layered MOFs critically depend on the degree of ordering between layers. We show that the impact of the two coupling sources in these materials can be discerned or enhanced by the displacement of the SBUs along the long or short molecular axes. The effects of vibronic spectral signatures are examined in both perturbative and resonance regimes. Although, to the best of our knowledge, displacement engineering in layered MOFs currently remains beyond reach, the findings reported here offer new details on the photophysical structure–property relationships in layered MOFs and provide suggestions on how to combine elements of molecular design and engineering to achieve desirable properties and functions for nano- and mesoscale optoelectronic applications.
Axisymmetric thin film flow on a flat disk foil subject to intense radial electric fields
Authors: Wang Z. , Zhang C. , Xia H. , Xie Q. , Deng W.
Published: January 2022

The presence of intense radial electric fields on a wetted disk foil of fingernail size results in the formation of a large number (up to ∼1000) of cone-jets and electrosprays (Wang et al., “Massively multiplexed electrohydrodynamic tip streaming from a thin disc,” Phys. Rev. Lett., 126, 064502, 2021). This massively multiplexed electrohydrodynamic tip streaming phenomenon offers a simple and convenient way of creating quasi-monodisperse droplets at high throughput. The structure of the axisymmetric liquid film flow on the disk determines the number and distribution of the cone-jets. In this work, we quantitively study the flow of the axisymmetric thin liquid film subjected to a radial electric field. The liquid film profile is found to be concave with a circular ridge, at which multiple Taylor cones are anchored. The liquid film thickness is experimentally quantified with a fluorescence imaging method, and the results are in decent agreement with the film profile model based on the lubrication theory. The velocity field in the liquid film was experimentally obtained by particle tracking velocimetry (PTV). The results shed light on the understanding of the multiplexed electrohydrodynamic tip streaming from a thin disk.
Rank-reduced coupled-cluster. III. Tensor hypercontraction of the doubles amplitudes
Authors: Hohenstein Edward G. , Fales B. Scott , Parrish Robert M. , Martínez Todd J.
Published: January 2022

We develop a quartic-scaling implementation of coupled-cluster singles and doubles (CCSD) based on low-rank tensor hypercontraction (THC) factorizations of both the electron repulsion integrals (ERIs) and the doubles amplitudes. This extends our rank-reduced (RR) coupled-cluster method to incorporate higher-order tensor factorizations. The THC factorization of the doubles amplitudes accounts for most of the gain in computational efficiency as it is sufficient, in conjunction with a Cholesky decomposition of the ERIs, to reduce the computational complexity of most contributions to the CCSD amplitude equations. Further THC factorization of the ERIs reduces the complexity of certain terms arising from nested commutators between the doubles excitation operator and the two-electron operator. We implement this new algorithm using graphical processing units and demonstrate that it enables CCSD calculations for molecules with 250 atoms and 2500 basis functions using a single computer node. Furthermore, we show that the new method computes correlation energies with comparable accuracy to the underlying RR-CCSD method.
Genetic evaluation to design a reference cow population for the Holstein breed in Tunisia: a first step toward genomic selection
Authors: Bakri Nour Elhouda , Djemali M’Naouer , Sarti Francesca Maria , Benyedder Mohamed , Pieramati Camillo
Published: January 2022

Context There is a large gap between developed and developing countries in the field of genetic evaluation of livestock animals. Introduction of genomic evaluation procedures and methods could contribute to reducing this gap. Aims The goal of this study was to select a reference cow population for the Holstein breed in Tunisia. Specific objectives were to update adjustments for non-genetic factors affecting milk yield, estimate genetic parameters for milk yield, and predict cow breeding values. Methods A BLUP animal model was used for 11 175 lactations recorded between 2012 and 2017 from 6251 dairy cattle raised in 33 Holstein dairy herds from three types of herds or production sectors. A pedigree file of 16 211 males and females was included in the genetic evaluation. Multiplicative adjustment factors were computed for age and month of calving, using adjusted 305 days in milk. Key results Month of calving, age at calving and farm ownership were significant sources of variation for milk yield. Cows calving in autumn and early winter (September–January) yielded more milk than those calving in spring (February–May) by 430 kg, and summer (June–August) by 455 kg. Holstein cows in Tunisia reached their maximum milk yield during the fourth lactation. Average adjusted milk yield for days in milk, month and age of calving was 6621 ± 2883 kg. Heritability estimates of adjusted milk yield were 0.14 ± 0.02 for all seven lactations and 0.16 ± 0.03 for the three first lactations. Phenotypic correlations among lactations were all positive, ranging from 0.25 to 0.43. On the basis of two main traditional designs (extreme yield and top accuracy), 1000 cows were selected to form the Tunisian female reference population. Conclusion The first step of genomic evaluation has been realised by forming a reference population from cows selected for adjusted milk yield production, based on their predicted breeding values and accuracies, using a BLUP animal model. Implication In the absence of progeny testing and sufficient proven sires, a cow reference population could represent the alternative for implementing genomic selection in developing countries.
Taxonomic revision reveals potential impacts of Black Summer megafires on a cryptic species
Authors: Jolly Chris J. , Moore Harry A. , Cowan Mitchell A. , Cremona Teigan , Dunlop Judy A. , Legge Sarah M. , Linley Grant D. , Miritis Vivianna , Woinarski John C. Z. , Nimmo Dale G.
Published: January 2022

Context Sound taxonomy is the cornerstone of biodiversity conservation. Without a fundamental understanding of species delimitations, as well as their distributions and ecological requirements, our ability to conserve them is drastically impeded. Cryptic species – two or more distinct species currently classified as a single species – present a significant challenge to biodiversity conservation. How do we assess the conservation status and address potential drivers of extinction if we are unaware of a species’ existence? Here, we present a case where the reclassification of a species formerly considered widespread and secure – the sugar glider (Petaurus breviceps) – has dramatically increased our understanding of the potential impacts of the catastrophic 2019–20 Australian megafires to this species. Methods We modelled and mapped the distribution of the former and reclassified sugar glider (Petaurus breviceps). We then compared the proportional overlap of fire severity classes between the former and reclassified distribution, and intersected habitat suitability and fire severity to help identify areas of important habitat following the 2019–20 fires. Key results Taxonomic revision means that the distribution of this iconic species appears to have been reduced to 8% of its formerly accepted range. Whereas the 2019–20 Australian megafires overlapped with 8% of the formerly accepted range, they overlapped with 33% of the proposed range of the redefined Petaurus breviceps. Conclusions Our study serves as a sombre example of the substantial risk of underestimating impacts of mega-disturbance on cryptic species, and hence the urgent need for cataloguing Earth’s biodiversity in the age of megafire.
Electrostatic tweezer for droplet manipulation
Authors: Jin Yuankai , Xu Wanghuai , Zhang Huanhuan , Li Ruirui , Sun Jing , Yang Siyan , Liu Minjie , Mao Haiyang , Wang Zuankai
Published: January 2022

Significance

The manipulation of liquid droplets plays a crucial role in multidisciplinary applications. However, existing methods still face many challenges, such as short distance, low velocity, restricted operating conditions, the need for extra responsive additives in droplet, and so on. To circumvent these constraints, here we develop a droplet electrostatic tweezer to trap the liquid droplet or faithfully guide the droplet motion in a remote manner. Our method allows high flexibility and precision in manipulating droplets of different types, volumes, and numbers under different working conditions, such as in open and closed spaces and on flat and tilted surfaces as well as in oil medium, imparting various applications, such as high-throughput and high-sensitivity Raman detection.
Trajectories and Outcomes of Those Not Criminally Responsible on Account of Mental Disorder through a Canadian Forensic System
Authors: Cheng Jeremy , Olver Mark E. , Haag Andrew M. , Wormith J. Stephen
Published: January 2022

Canadians adjudicated Not Criminally Responsible on Account of Mental Disorder (NCR) are detained in forensic psychiatric hospitals under a jurisdictional review board (RB) governed by the Canadian Criminal Code. The custody and management of NCR populations are administered independently across jurisdictions despite being federally legislated, and research is limited on how RBs may vary in their efforts to balance public safety and social reintegration across cases, settings, and provinces. To this end, the trajectories and outcomes were investigated in one understudied Canadian RB system on a sample of NCR individuals ( n = 109) and compared to other provincial practices. A retrospective longitudinal design was employed to track an NCR cohort between 2005 and 2010 until 2015. Results demonstrated that the provincial RB aligned their operational and management practices with federal legislation, but unique deviations contributed to novel NCR trajectories and outcomes under RB supervision that were conservative relative to provincial partners. Dispositions varied as a function of risk level and were informed by clinician recommendations. Detention length differences were observed between ancestral lines, as the White ancestral group spent an average of three years less in custody than the Nonwhite ancestral group despite limited differences in demographic, clinical, and criminogenic profiles. Further research is required on NCR trajectories and outcomes across other understudied provinces and the role of forensic risk instruments in assisting with the consistent application of federal law.
Estimating the memory parameter for potentially non-linear and non-Gaussian time series with wavelets
Authors: Xu Chen , Zhang Ye
Published: January 2022

The asymptotic theory for the memory-parameter estimator constructed from the log-regression with wavelets is incomplete for 1/f processes that are not necessarily Gaussian or linear. Having a complete version of this theory is necessary because of the importance of non-Gaussian and non-linear long-memory models in describing financial time series. To bridge this gap, we prove that, under some mild assumptions, a newly designed memory estimator, named LRMW in this paper, is asymptotically consistent. The performances of LRMW in three simulated long-memory processes indicate the efficiency of this new estimator.
UV-induced dissociation of CH2BrI probed by intense femtosecond XUV pulses
Authors: Köckert Hansjochen , Lee Jason W L , Allum Felix , Amini Kasra , Bari Sadia , Bomme Cédric , Brauße Felix , Brouard Mark , Burt Michael , Cunha de Miranda Barbara , Düsterer Stefan , Eng-Johnsson Per , Erk Benjamin , Géléoc Marie , Geneaux Romain , Gentleman Alexander S , Guillemin Renaud , Goldsztejn Gildas , Holland David M P , Ismail Iyas , Journel Loïc , Kierspel Thomas , Küpper Jochen , Lahl Jan , Mackenzie Stuart R , Maclot Sylvain , Manschwetus Bastian , Mereshchenko Andrey S , Mullins Terence , Olshin Pavel K , Palaudoux Jérôme , Penent Francis , Piancastelli Maria Novella , Rompotis Dimitrios , Rouzée Arnaud , Ruchon Thierry , Rudenko Artem , Schirmel Nora , Simon Marc , Techert Simone , Travnikova Oksana , Trippel Sebastian , Vallance Claire , Wang Enliang , Wiese Joss , Ziaee Farzaneh , Marchenko Tatiana , Rolles Daniel , Boll Rebecca
Published: January 2022

The ultraviolet (UV)-induced dissociation and photofragmentation of gas-phase CH2BrI molecules induced by intense femtosecond extreme ultraviolet (XUV) pulses at three different photon energies are studied by multi-mass ion imaging. Using a UV-pump–XUV-probe scheme, charge transfer between highly charged iodine ions and neutral CH2Br radicals produced by C–I bond cleavage is investigated. In earlier charge-transfer studies, the center of mass of the molecules was located along the axis of the bond cleaved by the pump pulse. In the present case of CH2BrI, this is not the case, thus inducing a rotation of the fragment. We discuss the influence of the rotation on the charge transfer process using a classical over-the-barrier model. Our modeling suggests that, despite the fact that the dissociation is slower due to the rotational excitation, the critical interatomic distance for charge transfer is reached faster. Furthermore, we suggest that charge transfer during molecular fragmentation may be modulated in a complex way.
Effect of atmospheric-pressure plasma irradiation on the surface tension of water
Authors: Shirai Naoki , Kaneko Takuma , Takamura Yuto , Sasaki Koichi
Published: January 2022

We have shown that measuring the surface tension is a useful scheme to examine the plasma–liquid interface in real-time. The surface tension was measured using a method based on the dispersion relation of an acoustic capillary wave excited on the water surface. The surface tension gradually increased with time, when the water surface was irradiated with the outside region of the spatial afterglow of an atmospheric-pressure plasma. The Marangoni effect associated with the localized increase in the surface tension was observed during the plasma irradiation. The surface tension decreased after the termination of the discharge. A correlation was found between the transient decrease in the surface tension and the variation of the OH radical density in the gas phase. No increase in the surface tension was observed in the solution containing a trapping agent for liquid-phase OH radicals. These experimental results suggest that OH radicals act to increase the surface tension. However, the behavior of the surface tension cannot be explained perfectly by considering only the action of OH radicals.
Quadruple plasmon-induced transparency and tunable multi-frequency switch in monolayer graphene terahertz metamaterial
Authors: Li Yuhui , Xu Yiping , Jiang Jiabao , Ren Liyong , Cheng Shubo , Yang Wenxing , Ma Chengju , Zhou Xianwen , Wang Ziyi , Chen Zhanyu
Published: January 2022

A monolayer graphene metamaterial composed of a graphene block and four graphene strips, which has the metal-like properties in terahertz frequency range, is proposed to generate an outstanding quadruple plasmon-induced transparency (PIT). Additional analyses show that the forming physical mechanism of the PIT with four transparency windows can be explained by strong destructive interference between the bright mode and the dark mode, and the distributions of electric field intensity and electric field vectors under the irradiation of the incident light. Coupled mode theory and finite-difference time-domain method are employed to study the spectral response characteristics of the proposed structure, and the theoretical and simulated results are in good agreement. It is found that a tunable multi-frequency switch and excellent optical storage can be achieved in the wide PIT window. The maximum modulation depth is up to 99.7%, which corresponds to the maximum extinction ratio of 25.04 dB and the minimum insertion loss of 0.19 dB. In addition, the time delay is as high as 0.919 ps, the corresponding group refractive index is up to 2755. Thus, the proposed structure provides a new method for the design of terahertz multi-frequency switches and slow light devices.
Global weak solutions to fully cross-diffusive systems with nonlinear diffusion and saturated taxis sensitivity
Authors: Fuest Mario
Published: January 2022

Systems of the type

u

t

=
∇
⋅

(

D

1

(

u

)

∇
u
−

S

1

(

u

)

∇
v

)

+

f

1

(

u
,
v

)

,

v

t

=
∇
⋅

(

D

2

(

v

)

∇
v
+

S

2

(

v

)

∇
u

)

+

f

2

(

u
,
v

)

(

⋆

)

can be used to model pursuit-evasion relationships between predators and prey. Apart from local kinetics given by f
1 and f
2, the key components in this system are the taxis terms −∇ ⋅ (S
1(u)∇v) and +∇ ⋅ (S
2(v)∇u); that is, the species are not only assumed to move around randomly in space but are also able to partially direct their movement depending on the nearby presence of the other species. In the present article, we construct global weak solutions of (⋆) for certain prototypical nonlinear functions D

i
, S

i
and f

i
, i ∈ {1, 2}. To that end, we first make use of a fourth-order regularisation to obtain global solutions to approximate systems and then rely on an entropy-like identity associated with (⋆) for obtaining various a priori estimates.
Decay of correlations for weakly expanding dynamical systems with Dini potentials under optimal quasi-gap condition
Authors: Jiang Yunping , Ye Yuan-Ling
Published: January 2022

We find an optimal quasi-gap condition for a weakly expanding dynamical system associated with Dini potential. Under this optimal quasi-gap condition, we prove the Ruelle operator theorem and further the decay of the correlations for any weakly expanding dynamical systems with Dini potentials.
Weighted L
2-contractivity of Langevin dynamics with singular potentials
Authors: Camrud Evan , Herzog David P , Stoltz Gabriel , Gordina Maria
Published: January 2022

Convergence to equilibrium of underdamped Langevin dynamics is studied under general assumptions on the potential U allowing for singularities. By modifying the direct approach to convergence in L
2 pioneered by Hérau and developed by Dolbeault et al, we show that the dynamics converges exponentially fast to equilibrium in the topologies L
2(dμ) and L
2(W* dμ), where μ denotes the invariant probability measure and W* is a suitable Lyapunov weight. In both norms, we make precise how the exponential convergence rate depends on the friction parameter γ in Langevin dynamics, by providing a lower bound scaling as min(γ, γ
−1). The results hold for usual polynomial-type potentials as well as potentials with singularities such as those arising from pairwise Lennard-Jones interactions between particles.
Physics of runaway electrons with shattered pellet injection at JET
Authors: Reux C , Paz-Soldan C , Eidietis N , Lehnen M , Aleynikov P , Silburn S , Bandaru V , Ficker O , Hoelzl M , Hollmann E M , Jachmich S , Joffrin E , Lomas P J , Rimini F , Baylor L , Bleasdale A , Calacci L , Causa F , Carnevale D , Coffey I , Craven D , Dal Molin A , de la Luna E , De Tommasi G , Garcia J , Gebhart T , Giacomelli L , Huber A , Khilkevich E , Lowry C , Macusova E , Manzanares A , Nocente M , Panontin E , Papp G , Pautasso G , Peacock A , Plyusnin V , Shevelev A , Shiraki D , Sommariva C , Sozzi C , Sridhar S , Sweeney R , Szepesi G , Tinguely R A , Wilson J
Published: January 2022

Runaway electrons (REs) created during tokamak disruptions pose a threat to the reliable operation of future larger machines. Experiments using shattered pellet injection (SPI) have been carried out at the JET tokamak to investigate ways to prevent their generation or suppress them if avoidance is not sufficient. Avoidance is possible if the SPI contains a sufficiently low fraction of high-Z material, or if it is fired early in advance of a disruption prone to runaway generation. These results are consistent with previous similar findings obtained with Massive Gas Injection. Suppression of an already accelerated beam is not efficient using High-Z material, but deuterium leads to harmless terminations without heat loads. This effect is due to the combination of a large magnetohydrodynamic instability scattering REs on a large area and the absence of runaway regeneration during the subsequent current collapse thanks to the flushing of high-Z impurities from the runaway companion plasma. This effect also works in situations where the runaway beam moves upwards and undergoes scraping-off on the wall.
Physics-based control of neoclassical tearing modes on TCV
Authors: Kong M , Felici F , Sauter O , Galperti C , Vu T , Ham C J , Hender T C , Maraschek M , Reich M
Published: January 2022

This paper presents recent progress in studies of neoclassical tearing modes (NTMs) on TCV, concerning the new physics learned and how this physics contributes to a better real-time (RT) control of NTMs. A simple technique that adds a small (sinusoidal) sweeping to the target electron cyclotron (EC) beam deposition location has proven effective both for the stabilization and prevention of

2

/

1

NTMs. This relaxes the strict requirement on beam-mode alignment for NTM control, which is difficult to ensure in RT. In terms of the EC power for NTM stabilization, a control scheme making use of RT island width measurements has been tested on TCV. NTM seeding through sawtooth (ST) crashes or unstable current density profiles (triggerless NTMs) has been studied in detail. A new NTM prevention strategy utilizing only transient EC beams near the relevant rational surface has been developed and proven effective for preventing ST-seeded NTMs. With a comprehensive modified Rutherford equation (co-MRE) that considers the classical stability both at zero and finite island width, the prevention of triggerless NTMs with EC beams has been simulated for the first time. The prevention effects are found to result from the local effects of the EC beams (as opposed to global current profile changes), as observed in a group of TCV experiments scanning the deposition location of the preemptive EC beam. The co-MRE has also proven able to reproduce well the island width evolution in distinct plasma scenarios on TCV, ASDEX Upgrade and MAST, with very similar constant coefficients. The co-MRE has the potential to be applied in RT to provide valuable information, such as the EC power required for NTM control with RT-adapted coefficients, contributing to both NTM control and integrated control with a limited set of actuators.
Muon spin rotation and relaxation study on topological noncentrosymmetric superconductor PbTaSe2
Authors: Zhu Z H , Tan C , Zhang J , Biswas P K , Hillier A D , Wang M X , Yang Y X , Chen C S , Ding Z F , Li S Y , Shu L
Published: January 2022

Topological superconductivity is an exotic phenomenon due to the symmetry-protected topological surface state, in which a quantum system has an energy gap in the bulk but supports gapless excitations confined to its boundary. Symmetries including central and time-reversal symmetry (TRS), along with their relations with topology, are crucial for topological superconductivity. We report muon spin relaxation/rotation (μSR) experiments on a topological noncentrosymmetric superconductor PbTaSe2 to study its TRS and gap symmetry. Zero-field μSR experiments indicate the absence of internal magnetic field in the superconducting state, consistent with previous μSR results. Furthermore, transverse-field μSR measurements reveals that the superconducting gap of PbTaSe2 is an isotropic three-dimensional fully-gapped single-band. The fully-gapped results can help understand the pairing mechanism and further classify the topological superconductivity in this system.
Investigation of negative-parity states in 16C via deuteron inelastic scattering *
Authors: Tan Z. W. , Lou J. L. , Ye Y. L. , Liu Y. , Pang D. Y. , Yuan C. X. , Li J. G. , Liu W. , Jiang Y. , Yang B. , Tao L. C. , Ma K. , Li Z. H. , Li Q. T. , Yang X. F. , Xu J. Y. , Yu H. Z. , Han J. X. , Bai S. W. , Huang S. W. , Li G. , Wu H. Y. , Zang H. L. , Feng J. , Wang J. S. , Yang Y. Y. , Ma P. , Hu Q. , Bai Z. , Gao Z. H. , Duan F. F. , Hu L. Y. , Tan J. H. , Sun S. Q. , Song Y. S. , Ong H. J. , Tran D. T. , Zhu H. Y. , Xia B. L.
Published: January 2022

Two low-lying unbound states in 16C are investigated by deuteron inelastic scattering in inverse kinematics. Besides the 2

state at 5.45 MeV previously measured in a 1n knockout reaction, a new resonant state at 6.89 MeV is observed for the first time. The inelastic scattering angular distributions of these two states are well reproduced by the distorted-wave Born approximation (DWBA) calculation with an l = 1 excitation. In addition, the spin-parities of the unbound states are discussed and tentatively assigned based on shell model calculations using the modified YSOX interaction.
Radiative Diffusion in a Time-dependent Outflow: a Model for Fast Blue Optical Transients
Authors: Chen Chun , Shen Rong-Feng
Published: January 2022

Fast Blue Optical Transients (FBOTs) are luminous transients with fast evolving (typically t
rise < 12 days) light curve and blue color (usually −0.2 > g-r > −0.3) that cannot be explained by a supernova-like explosion. We propose a radiative diffusion in a time-dependent outflow model to interpret such special transients. In this model, we assume that a central engine ejects continuous outflow during a few days. We consider the ejection of the outflow to be time-dependent. The outflow is optically thick initially and photons are frozen in it. As the outflow expands over time, photons gradually escape, and our work is to model such an evolution. Numerical and analytical calculations are considered separately, and the results are consistent. We apply the model to three typical FBOTs: PS1-10bjp, ZTF18abukavn, and ATLAS19dqr. The modeling finds the total mass of the outflow (∼1–5 M
⊙), and the total time of the ejection (∼a few days) for them, leading us to speculate that they may be the result of the collapse of massive stars.
A simple method of UV stray light correction for field spectrometers in Ground Validation Sites
Authors: Li L , Wu Z , Woolliams E R , Dai C , Wang Y
Published: January 2022

Field spectrometers are widely applied in ground validation sites for remote sensing. However, the control of stray light is one of the most important factors to ensure accurate measurements, since the spectral distribution of target source differs significantly from the laboratory calibration source. Here, a simple UV stray light correction method for continuously distributed wide-spectrum light sources was established by using a set of bandpass filters. This analysis enabled a simple, low-cost method for correcting for the observed straylight.
Advancements in NRC’s Primary Spectral Irradiance Scale Realization
Authors: Gamouras A , Woods D J , Côté É , Gaertner A A
Published: January 2022

The National Research Council (NRC) of Canada has been working to establish new facilities and to improve measurement capabilities traceable to the International System of Units (SI units) in optical radiometry. The NRC primary spectral irradiance scale has transitioned from a detector-based approach in the range of 700 nm to 1600 nm to a detector and source-based realization from 250 nm to 2500 nm. A high temperature blackbody (HTBB) acts as the primary light source for the calibration of 1000 W FEL spectral irradiance standard lamps. The thermodynamic temperature of the HTBB is determined using an NRC-designed wide-band filter radiometer, with spectral responsivity SI-traceable to the NRC optical power scale. This new facility has significantly improved measurement uncertainties compared to the previous NRC spectral irradiance scale.
Optical power scale realization using the predictable quantum efficient detector
Authors: Maham Kinza , Kärhä Petri , Manoocheri Farshid , Ikonen Erkki
Published: January 2022

We report realization of scales for optical power of lasers and spectral responsivity of laser power detectors based on a predictable quantum efficient detector (PQED) over the spectral range of 400 nm–800 nm. The PQED is characterized and used to measure optical power of a laser that is further used in calibration of the responsivities of a working standard trap detector at four distinct laser lines, with an expanded uncertainty of about 0.05%. We present a comparison of responsivities calibrated against the PQED at Aalto and the cryogenic radiometer at RISE, Sweden. The measurement results support the concept that the PQED can be used as a primary standard of optical power.
Calibration of a modular trap detector system towards a new realisation of the luminous intensity unit
Authors: Schneider Philipp , Nevas Saulius , Lindner Detlef , Werner Lutz , Linke Ulrike , Sperling Armin
Published: January 2022

A modular photometric trap detector system has recently been developed at Physikalisch-Technische Bundesanstalt (PTB). All parts of the detector are now completely calibrated. The new planned traceability chain for the realisation of luminous intensity unit can therefore be established for the first time. This contribution shows the results of the individual calibration steps including the associated measurement uncertainties and correlations. A major part of the calibrations along the traceability chain is done at the upgraded measurement setup TULIP (TUnable Lasers In Photometry). The improvements of the TULIP setup are presented and the effects on the measurement uncertainty are shown. The result of the first complete calibration according to the new traceability chain is compared to previous calibration results both in terms of spectral irradiance responsivity and luminous responsivity. The further steps required towards implementing the new traceability chain and the possible implications are discussed.
Polarization Characterization of LEDs by Stokes Parameters Measurements
Authors: Saito T , Sutani T , Kiyono K , Oikawa T
Published: January 2022

Stokes parameters have been measured by using a polarimeter consisting of a rotating phase plate before a fixed polarizer for bullet-shaped red, green and blue LEDs at 3 different directions of 0°, 45° and 90° from the principal axis. The degree of polarization is minimum at the observation angle 0° (observed head-on) for all colors as expected but has non-zero values (1-9%). As for the possible cause for the partial polarization, it is likely to be brought by striae inside the transparent epoxy resin that can be easily visible. Data at observation angle 90° have features common for all colors; the degree of polarization is highest, the long axis azimuth of the polarization ellipse is nearly in the horizontal direction, and the ellipticity is small. These features can be explained as follows. At observation angle 90°, only small fraction of the beam emitted nearly horizontally is detected possibly through multireflection (the plane of incidence is in the vertical plane) inside the top- and bottom-surfaces (in the horizontal direction) of the chip substrate. Since the reflectance for s-polarization (horizontal component) is higher than that for p-polarization, the emerging beam becomes horizontally polarized. The hypotheses that geometrical asymmetry generates polarization is experimentally supported.
Novel LED-based radiation source and its application in diffuse reflectometry and polarization measurements
Authors: Santourian I , Quast T , Teichert S , Hauer K-O , Schirmacher A
Published: January 2022

An LED sphere radiator (LED-SR) was constructed to improve the accuracy in spectral radiance factor measurements performed with the robot-based gonioreflectometer at PTB. Its properties with respect to the spectral range and coverage, the temporal stability, and the homogeneity of the radiation field are presented. Two types of matte ceramic reflection standards were used for spectral radiance factor validation measurements comparing the standardly used halogen sphere radiator (Halogen-SR) and the LED-SR. Due to its designed spectral range at the border between the visible and the UV-A spectral range, the LED-SR is well suited for many applications in diffuse reflectometry. Its use for absolute radiance factor measurements and investigations of the fluorescence properties of diffuse reflecting samples is shown. Reliable polarization-resolved measurements at wavelengths below 430 nm could be carried out with PTB’s gonioreflectometer for the first time due to the beneficial signal-to-noise ratio of the LED-SR.
Applicability of DIN 5036-3 to Transmittance Haze Measurement
Authors: Liu Wen-Chun , Yu Hsueh-Ling
Published: January 2022

This paper evaluates the applicability of the method described in DIN 5036-3 for transmittance haze measurement, theoretically and experimentally. It is shown that DIN 5036-3 is valid for total transmittance measurement. However, when applying to diffuse transmittance measurement, the measured value is lower than the theoretical one, resulting a lower value of calculated transmittance haze. The reflectance of the integrating sphere and collimation of the incident beam are the keys to achieve better agreement between theory and experiment. Further study is necessary to recommend solutions for the discovered issues.
CHARACTERIZATION OF BIDIRECTIONAL TRANSMISSIVE AND REFLECTIVE PROPERTIES OF BLACK SILICON
Authors: Georgiev Georgi T. , Butler James J. , Shiri Ron , Jhabvala Christine A.
Published: January 2022

This paper describes the initial work of characterizing the transmissive and reflective properties of black silicon diffusers. The diffusers were fabricated from a 100 mm diameter black silicon sample at NASA’s Goddard Space Flight Center (GSFC). The directional hemispherical reflectance from 250 nm to 2500 nm and BRDF/BTDF measurements at 632.8 nm, 1064 nm, and 1550 nm were measured using the GSFC Diffuser Calibration Laboratory’s (DCL) spectrophotometer and optical scatterometer. The diffusers exhibit a low level of specular reflection up to ~1100 nm with no evidence of retroscatter. The measurements are traceable to those made at the National Institute of Standards and Technology (NIST).
Advocating a statistical definition for the BRDF
Authors: Chavel P , Sortais Y , Labardens T , Simonot L , Hébert M , Obein G.
Published: January 2022

The definition of BRDF as a ratio of radiance to irradiance assumes that the geometrical optics framework applies, implicitly meaning that spatial coherence and diffraction of light have no significant effect in the reflection process. However, recent applications of BRDF push at increasing the angular resolution and thus at reducing the solid angles for illumination and collection. Therefore speckle, an optical effect inherent to the stochastic nature of scattering objects, becomes apparent. We suggest that BRDF should be redefined as the statistical average over that effect.
Comparison of back focal plane imaging of nitrogen vacancy centers in nanodiamond and core-shell CdSe/CdS quantum dots
Authors: Christinck J , Rodiek B , López M , Georgieva H , Hofer H , Götzinger S , Kück S
Published: January 2022

We report on the characterization of the angular-dependent emission of two different single-photon emitters based on nitrogen-vacancy centers in nanodiamond and on core-shell CdSe/CdS quantum dot nanoparticles. The emitters were characterized in a confocal microscope setup by spectroscopy and Hanbury-Brown and Twiss interferometry. The angular-dependent emission is measured using a back focal plane imaging technique. A theoretical model of the angular emission patterns of the 2D dipoles of the emitters is developed to determine their orientation. Experiment and model agree well with each other.