bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnostic Performance of a Particle Gel Immunoassay in Vaccine-Induced Immune Thrombotic Thrombocytopenia
Authors: Uzun Günalp , Althaus Karina , Hammer Stefanie , Wanner Yvonne , Nowak-Harnau Stefanie , Enkel Sigrid , Bakchoul Tamam
Published: February 2023

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare but serious complication of adenoviral vector-based COVID-19 vaccines. Similar to heparin-induced thrombocytopenia (HIT), antibodies reacting to platelet factor 4 (PF4) are responsible for platelet activation in VITT. The diagnosis of VITT includes the detection of anti-PF4 antibodies. Particle gel immunoassay (PaGIA) is one of the rapid immunoassays that is commonly used in the diagnosis of HIT to detect anti-PF4 antibodies. The aim of this study was to investigate the diagnostic performance of PaGIA in patients suspected of VITT. In this retrospective, single-center study, the correlation between PaGIA, enzyme immunoassay (EIA), and modified heparin-induced platelet aggregation assay (HIPA) in patients with findings suggestive of VITT was investigated. A commercially available PF4 rapid immunoassay (ID PaGIA H/PF4, Bio-Rad-DiaMed GmbH, Switzerland) and an anti-PF4/heparin EIA (ZYMUTEST HIA IgG, Hyphen Biomed) were used according to manufacturer's instructions. Modified HIPA was accepted as the gold standard test. Between March 8 and November 19, 2021, a total of 34 samples from clinically well-characterized patients (14 males, 20 females, mean age: 48.2 ± 18.2 years) were analyzed with PaGIA, EIA, and modified HIPA. VITT was diagnosed in 15 patients. Sensitivity and specificity of PaGIA were 54 and 67%, respectively. Anti-PF4/heparin optical density values were not significantly different between PaGIA positive and negative samples (p = 0.586). The sensitivity and specificity of EIA, on the other hand, were 87 and 100%, respectively. In conclusion, PaGIA is not reliable in the diagnosis of VITT because of its low sensitivity and specificity.
Inherited Platelet Disorders: A Short Introduction
Authors: Zieger Barbara , Boeckelmann Doris
Published: February 2023

Platelets play an important role regarding coagulation by contributing to thrombus formation by platelet adhesion, aggregation, and α-/δ-granule secretion. Inherited platelet disorders (IPDs) are a very heterogeneous group of disorders that are phenotypically and biochemically diverse. Platelet dysfunction (thrombocytopathy) can be accompanied by a reduction in the number of thrombocytes (thrombocytopenia). The extent of the bleeding tendency can vary greatly. Symptoms comprise mucocutaneous bleeding (petechiae, gastrointestinal bleeding and/or menorrhagia, epistaxis) and increased hematoma tendency. Life-threatening bleeding can occur after trauma or surgery. In the last years, next-generation sequencing had a great impact on unrevealing the underlying genetic cause of individual IPDs. Because IPDs are so diverse, a comprehensive analysis of platelet function and genetic testing is indispensable.
Patienten mit ersten Anzeichen nachlassender geistiger Leistungsfähigkeit: Was der Hausarzt nicht vergessen sollte
Authors: Emmrich Peter
Published: February 2023

Noch immer wird die leichte kognitive Störung zu selten diagnostiziert und ärztlich behandelt. Dabei haben Forschungen der letzten Jahre gezeigt, dass verschiedene Maßnahmen das Risiko nachlassender geistiger Leistungsfähigkeit und einer eventuellen sukzessiven Demenzerkrankung mindern können. Erste Gedächtnisverluste, Verhaltensänderungen oder neuropsychiatrische Störungen im Alter sollte der Arzt nicht nur mit dem Ziel ernst nehmen, weitere Einbußen zu verzögern. Vielmehr können Patienten lange vor demenziellen Stadien bereits unter diesen Beeinträchtigungen leiden. Zu den modifizierbaren Risikofaktoren für Demenzen zählen u. a. Hörverlust, Bluthochdruck, übermäßiger Alkoholkonsum, Übergewicht, Rauchen, Depressionen, Einsamkeit, körperliche Inaktivität und Diabetes. Zur symptomatischen Behandlung altersbedingter kognitiver Beeinträchtigungen und demenzieller Erkrankungen trägt der Ginkgo-biloba-Extrakt EGb 761 bei. Aufgrund der guten Verträglichkeit von EGb 761 empfiehlt sich daher der frühzeitige Einsatz im Rahmen eines ganzheitlichen Therapiekonzepts.
Update Motorisches Lernen (1) Definitionen – Unterscheidungen – Theorien
Authors: Steck Gail Cox , Janssen Christina
Published: February 2023

Der nachfolgende erste Beitrag stellt Definitionen, Unterscheidungen und Theorien dar. Der zweite Beitrag (► Seite 22) erläutert das „Lernrad“ zum Prozess und die strukturierte Anwendung des motorischen Lernens in der Praxis. Der dritte Artikel vermittelt Beispiele für lernfördernde Instruktionsarten (► Seite 24).
Isomeric dynamics of multi-soliton molecules in passively mode-locked fiber lasers
Authors: Huang Siyun , Liu Yusong , Liu Haoguang , Sun Yixiang , Xia Ran , Ni Wenjun , Luo Yiyang , Yan Lisong , Liu Huanhuan , Sun Qizhen , Shum Perry Ping , Tang Xiahui
Published: February 2023

The self-assembly of optical solitons propagating in nonlinear dissipative systems spreads the concept of soliton molecules. Assisted with the real-time spectral interferometry, plentiful internal dynamics has been probed within the multi-pulse patterns, emphasizing the striking analogies with the matter molecules. Therefrom, these particle-like behaviors would yield more intriguing landscapes toward the extended degrees of freedom considering increased constituents. Here, we transfer the concept of “isomer” to the experimental investigation on the unexplored isomeric dynamics of soliton molecules in parallel. Particularly, two isomers for soliton triplets and four isomers for soliton quadruplets are captured under different self-assembled forms, within each of which the binding separations and relative phases of the constituents are governed by mutual soliton interactions. With the diverse separation-phase evolving trajectories mapped in the interaction plane, detailed insights into the temporal distribution and the transient dynamics are displayed with respect to a panorama of the isomeric dynamics. The perspective of optical isomers shed new light on the analogy with matter molecules, and the underlying isomeric dynamics may stimulate the artificial manipulation of various soliton molecules for ultrafast applications.
External field induced defect transformation in circular confined Gay–Berne liquid crystals
Authors: Chen Zi-Qin , Sun Yu-Wei , Zhang Xiao-Jie , Zhu You-Liang , Li Zhan-Wei , Sun Zhao-Yan
Published: February 2023

Normally, defects in two-dimensional, circular, confined liquid crystals can be classified into four types based on the position of singularities formed by liquid crystal molecules, i.e., the singularities located inside the circle, at the boundary, outside the circle, and outside the circle at infinity. However, it is considered difficult for small aspect ratio liquid crystals to generate all these four types of defects. In this study, we use molecular dynamics simulation to investigate the defect formed in Gay–Berne, ellipsoidal liquid crystals, with small aspect ratios confined in a circular cavity. As expected, we only find two types of defects (inside the circle and at the boundary) in circular, confined, Gay–Berne ellipsoids under static conditions at various densities, aspect ratios, and interactions between the wall and liquid crystals. However, when introducing an external field to the system, four types of defects can be observed. With increasing the strength of the external field, the singularities in the circular, confined system change from the inside to the boundary and the outside, and the farthest position that the singularities can reach depends on the strength of the external field. We further introduce an alternating, triangular wave, external field to the system to check if we can observe the transformation of different defects within an oscillating period. We find that the position of the singularities greatly depends on the oscillating intensity and oscillating period. By changing the oscillating intensity and oscillating period of the external field, the defect types can be adjusted, and the transformation between different defects can be easily observed. This provides a feasible way to modulate liquid crystal defects and investigate the transformation between different defects.
Computational modeling of passive transport of functionalized nanoparticles
Authors: Moreno-Chaparro Daniela , Moreno Nicolas , Usabiaga Florencio Balboa , Ellero Marco
Published: February 2023

Functionalized nanoparticles (NPs) are complex objects present in a variety of systems ranging from synthetic grafted nanoparticles to viruses. The morphology and number of the decorating groups can vary widely between systems. Thus, the modeling of functionalized NPs typically considers simplified spherical objects as a first-order approximation. At the nanoscale label, complex hydrodynamic interactions are expected to emerge as the morphological features of the particles change, and they can be further amplified when the NPs are confined or near walls. Direct estimation of these variations can be inferred via diffusion coefficients of the NPs. However, the evaluation of the coefficients requires an improved representation of the NPs morphology to reproduce important features hidden by simplified spherical models. Here, we characterize the passive transport of free and confined functionalized nanoparticles using the Rigid Multi-Blob (RMB) method. The main advantage of RMB is its versatility to approximate the mobility of complex structures at the nanoscale with significant accuracy and reduced computational cost. In particular, we investigate the effect of functional groups’ distribution, size, and morphology over nanoparticle translational and rotational diffusion. We identify that the presence of functional groups significantly affects the rotational diffusion of the nanoparticles; moreover, the morphology of the groups and number induce characteristic mobility reduction compared to non-functionalized nanoparticles. Confined NPs also evidenced important alterations in their diffusivity, with distinctive signatures in the off-diagonal contributions of the rotational diffusion. These results can be exploited in various applications, including biomedical, polymer nanocomposite fabrication, drug delivery, and imaging.
Structural ordering governs stiffness and ductile-to-brittle transition in Al–Li alloys
Authors: Wang Shuo , Xue Chengpeng , Yang Xinghai , Wang Junsheng
Published: February 2023

The trade-off of stiffness and ductility of metals has long plagued materials scientists. To address this issue, atomic structure designs of short-range ordering (SRO) to sub-nanometer and nanometer scales have received much interest in tailoring the atomic environment and electronic interaction between solute and solvent atoms. Taking an example of Al–Li alloy with high specific stiffness and reverse correlation of Young’s modulus and melting point, in this work, we investigate the SRO-dependent stiffness and intrinsic ductile–brittle properties by performing a full-configuration strategy containing various structural ordering features. It suggests that the short-range ordered arrangement of Li atoms can effectively enhance the stiffness while keeping ductility, playing a hydrostatic pressure-like role. Our findings present fundamental knowledge to enable high stiffness and ductility for solvent phases with low modulus through designing local short-range ordered cluster structures.
The electron–phonon renormalization in the electronic structure calculation: Fundamentals, current status, and challenges
Authors: Shang Honghui , Yang Jinlong
Published: February 2023

Electron–phonon (e–ph) interaction plays a crucial role in determining many physical properties of the materials, such as the superconducting transition temperature, the relaxation time and mean free path of hot carriers, the temperature dependence of the electronic structure, and the formation of the vibrational polaritons. In the past two decades, the calculations of e–ph properties from first-principles has become possible. In particular, the renormalization of electronic structures due to e–ph interaction can be evaluated, providing greater insight into the quantum zero-point motion effect and the temperature dependence behavior. In this perspective, we briefly overview the basic theory, outline the computational challenges, and describe the recent progress in this field, as well as future directions and opportunities of the e–ph coupling calculations.
Linear scaling computation of forces for the domain-decomposition linear Poisson–Boltzmann method
Authors: Jha Abhinav , Nottoli Michele , Mikhalev Aleksandr , Quan Chaoyu , Stamm Benjamin
Published: February 2023

The Linearized Poisson–Boltzmann (LPB) equation is a popular and widely accepted model for accounting solvent effects in computational (bio-) chemistry. In the present article, we derive the analytical forces using the domain-decomposition-based LPB-method with a van-der Waals or solvent-accessible surface. We present an efficient strategy to compute the forces and its implementation, allowing linear scaling of the method with respect to the number of atoms using the fast multipole method. Numerical tests illustrate the accuracy of the computation of the analytical forces and compare the efficiency with other available methods.
Mode-dependent H atom tunneling dynamics of the S1 phenol is resolved by the simple topographic view of the potential energy surfaces along the conical intersection seam
Authors: Kim Junggil , Woo Kyung Chul , Kim Sang Kyu
Published: February 2023

Mode-dependent H atom tunneling dynamics of the O–H bond predissociation of the S1 phenol has been theoretically analyzed. As the tunneling is governed by the complicated multi-dimensional potential energy surfaces that are dynamically shaped by the upper-lying S1(ππ*)/S2(πσ*) conical intersection, the mode-specific tunneling dynamics of phenol (S1) has been quite formidable to be understood. Herein, we have examined the topography of the potential energy surface along the particular S1 vibrational mode of interest at the nuclear configurations of the S1 minimum and S1/S2 conical intersection. The effective adiabatic tunneling barrier experienced by the reactive flux at the particular S1 vibrational mode excitation is then uniquely determined by the topographic shape of the potential energy surface extended along the conical intersection seam coordinate associated with the particular vibrational mode. The resultant multi-dimensional coupling of the specific vibrational mode to the tunneling coordinate is then reflected in the mode-dependent tunneling rate as well as nonadiabatic transition probability. Remarkably, the mode-specific experimental result of the S1 phenol tunneling reaction [K. C. Woo and S. K. Kim, J. Phys. Chem. A 123, 1529–1537 (2019)] (in terms of the qualitative and relative mode-dependent dynamic behavior) could be well rationalized by semi-classical calculations based on the mode-specific topography of the effective tunneling barrier, providing the clear conceptual insight that the skewed potential energy surfaces along the conical intersection seam (strongly or weakly coupled to the tunneling reaction coordinate) may dictate the tunneling dynamics in the proximity of the conical intersection.
Simulated behaviour of wildland fire spreading through idealised heterogeneous fuels
Authors: Khan Nazmul , Sutherland Duncan , Moinuddin Khalid
Published: February 2023

Homogeneous vegetation is widely used in wildland fire behaviour models, although real vegetation is heterogeneous in nature and composed of different kinds of fuels and non-combustible parts. Many features of fires can arise from this heterogeneity. For land management and firefighting, creating heterogeneous fuel areas may be useful to reduce fire intensity and rate of spread (ROS), and alter fire geometry. Recently, an empirical model for fire spread in spinifex grasslands was developed and validated against experimental measurements. In this study, physics-based grassland fire behaviour simulations were conducted with varying percentages of fuel cover and alternating square and rectangular patches of burnable and non-burnable material. The environmental conditions and thermophysical properties of the grassland were kept constant throughout the simulation to separate the effects of fuel heterogeneities from other parameters. For three sets of nominal wind velocities, 3, 5.6 and 10 m s−1, we identified ‘go’ and ‘no go’ fires. Reasonable agreement between the non-dimensionalised simulated ROS and observed ROS in spinifex was found. There is a significant reduction of fire intensity, ROS, flame length, fire width and fire line length due to the heterogeneous effect of vegetation.
The analysis of hot deformation behaviour of low-cost α+β Ti-6Al-0.4V-1.2Fe alloys
Authors: Wan Guilin , Ren Zhihao , Guo Yanhua , Sun Zhonggang , Chang Hui
Published: February 2023

The low-cost Ti-6Al-0.4V-1.2Fe alloy was subjected to isothermal compression experiments on the Gleeble 3800, and the deformation temperature was 775°C∼975°C and the strain rate was 0.01 s−1∼10 s−1. Based on the experimental data on thermal deformation, the microstructure evolution was studied and the constitutive equation was developed. The experimental results show that the flow stress increased with increasing deformation temperature and with the increase of the strain rate; the optimal deformation temperature of Ti-6Al-0.4V-1.2Fe alloy is 820°C∼950°C, and the strain rate is 0.01 s−1∼0.32 s−1; During hot deformation, the primary softening mechanism of this alloy is continuous dynamic recrystallisation. Compared with Ti-6Al-4V, the Ti-6Al-0.4V-1.2Fe alloy has better hot workability and better plasticity.

Highlights A newly low-cost Ti-6Al-0.4V-1.2Fe alloy was designed based on the Kβ stability coefficient method, and the β stability coefficient was the same as that of Ti-6Al-4V. A study on the microstructure evolution in the process of hot deformation between Ti-6Al-0.4V-1.2Fe and Ti-6Al-4V alloys. A study on microstructure evolution and hot working process of a newly low-cost Ti-6Al-0.4V-1.2Fe alloy.
Precipitation behaviour and strengthening mechanisms of V-bearing 1800 MPa grade hot-stamping steel
Authors: Cheng Zhuo , Wang Shuize , Liu Jinyue , Wu Ruoqing , Gao Junheng , Wu Honghui , Li Tianyi , Wu Guilin , Mao Xinping
Published: February 2023

Achieving strength-ductility synergy of hot-stamping steel via microalloying technology has attracted great attention due to their pronounced precipitation strengthening. Nevertheless, the precipitation behaviours and characteristics have not been clearly unveiled. In this work, the effects of V content on the microstructure and mechanical properties of 1800 MPa grade hot-stamping steel are systematically studied. Massive V contained precipitates develop after hot-rolling and coiling, which refine the martensitic microstructure and retain in the matrix after austenitizing and quenching. The refined martensite with massive precipitates is responsible for the good mechanical properties. Generally, the tensile strength decreases slightly with increasing V content from 0.04% to 0.2%, as V consumes C in the martensite matrix by forming carbides and promoting precipitate coarsening.
Flat Band and ℤ2 Topology of Kagome Metal CsTi3Bi5
Authors: Wang Yuan , Liu Yixuan , Hao Zhanyang , Cheng Wenjing , Deng Junze , Wang Yuxin , Gu Yuhao , Ma Xiao-Ming , Rong Hongtao , Zhang Fayuan , Guo Shu , Zhang Chengcheng , Jiang Zhicheng , Yang Yichen , Liu Wanling , Jiang Qi , Liu Zhengtai , Ye Mao , Shen Dawei , Liu Yi , Cui Shengtao , Wang Le , Liu Cai , Lin Junhao , Liu Ying , Cai Yongqing , Zhu Jinlong , Chen Chaoyu , Mei Jia-Wei
Published: February 2023

The simple kagome-lattice band structure possesses Dirac cones, flat band, and saddle point with van Hove singularities in the electronic density of states, facilitating the emergence of various electronic orders. Here we report a titanium-based kagome metal CsTi3Bi5 where titanium atoms form a kagome network, resembling its isostructural compound CsV3Sb5. Thermodynamic properties including the magnetization, resistance, and heat capacity reveal the conventional Fermi liquid behavior in the kagome metal CsTi3Bi5 and no signature of superconducting or charge density wave (CDW) transition anomaly down to 85 mK. Systematic angle-resolved photoemission spectroscopy measurements reveal multiple bands crossing the Fermi level, consistent with the first-principles calculations. The flat band formed by the destructive interference of hopping in the kagome lattice is observed directly. Compared to CsV3Sb5, the van Hove singularities are pushed far away above the Fermi level in CsTi3Bi5, in line with the absence of CDW. Furthermore, the first-principles calculations identify the nontrivial ℤ2 topological properties for those bands crossing the Fermi level, accompanied by several local band inversions. Our results suppose CsTi3Bi5 as a complementary platform to explore the superconductivity and nontrivial band topology.
Lagrange-mesh calculations of P-wave resonances in three-body atomic systems
Authors: Servais Jean , Dohet-Eraly Jérémy
Published: February 2023

The resonance energies and widths of the P-wave states of helium and of the positronium ion are studied under the hypothesis that their constituting particles interact trough pure or screened Coulomb forces. The resonances are investigated by combining the Lagrange-mesh method and the complex scaling method. This approach is proved to be efficient: rather simple to implement, fast, and accurate. The obtained results improve by several orders of magnitude the best literature results.
Determination and assessment of a complete and self-consistent electron-neutral collision cross-section set for the C4F7N molecule
Authors: Zhang Boya , Hao Mai , Yao Yuyang , Xiong Jiayu , Li Xingwen , Murphy Anthony B , Sinha Nidhi , Antony Bobby , Ambalampitiya Harindranath B
Published: February 2023

The perfluoronitrile C4F7N is considered a promising SF6-alternative in high-voltage gas-insulated apparatus, thanks to its high dielectric strength and low global warming potential. However, a complete and consistent set of electron-neutral collision cross-sections of C4F7N is still lacking, which hinders relevant plasma modeling. In this contribution, the available electron-neutral collision cross-sections of C4F7N are first compiled and assessed. The initial cross-sections are adjusted iteratively by the electron swarm method to determine a complete and self-consistent cross-section set of C4F7N for the first time. The set is validated by a systematic comparison of electron swarm parameters between Boltzmann equation analysis and experimental measurements in pure C4F7N as well as C4F7N/N2 and C4F7N/Ar mixtures. The proposed cross-section set of C4F7N will be made available to the community in the LXCat database. It will be of particular importance for applications with an emphasis on the discharge mechanisms of this novel gas.
Ultra-compact active induced-magnetism Huygens’ metasurfaces: design and application
Authors: Qiu Chunqiao , Xue Chunhua , Yuan Luxi , Li Feng , Xu Quan , Zhu Hongyu , Li Quan , Zhang Zhengren
Published: February 2023

Recently, a new type of metasurface, the induced-magnetism Huygens’ metasurface, has attracted considerable attention due to its capability to manipulate electromagnetic waves. However, these studies mainly work in a passive way such that the functionalities are fixed once fabricated, limiting the device’s adaptability for practical applications and future commercialization. To comply with potential applications, further research endeavors need to be exerted to advance the reconfigurability and practicality. Herein, an ultra-compact and dynamically tunable design strategy of an induced-magnetism Huygens’ metasurface is proposed, whose basic unit is a pair of electric dipoles separated by a dielectric spacer and integrated with a varactor in each electric dipole. By simply changing the driven voltage of each unit, the transmission phase can be individually tuned in the near 2π range; meanwhile, the transmission amplitude remains very high. As a proof-of-concept demonstration, an active magnetism induced Huygens’ meta-lens is proposed to exhibit excellent dynamic wavefront manipulation performance. The proposed method may open an avenue toward planar lightweight low-cost dynamic wavefront manipulation devices.
Borel–Laplace sum rules with τ decay data, using OPE with improved anomalous dimensions
Authors: Ayala César , Cvetič Gorazd , Teca Diego
Published: February 2023

We perform numerical analysis of double-pinched Borel–Laplace QCD sum rules for the strangeless semihadronic τ-decay data. The D = 0 contribution to the theoretical contour integral in the sum rules is evaluated by the (truncated) Fixed Order perturbation theory method (FO) and by the Principal Value (PV) of the Borel integration. We use for the full Adler function the operator product expansion (OPE) with the terms ∼〈O

D
〉 of dimension D = 2n where 2 ≤ n ≤ 5 for the (V+A)-channel, and 2 ≤ n ≤ 7 for the V-channel data. In our previous works Ayala, Cvetič and Teca (2021, Eur. Phys. J. C
81 930), Ayala, Cvetič and Teca (2022, Eur. Phys. J. C
82 362), only the (V+A)-channel data was analysed. In this work, the analysis of a new set of V-channel data is performed as well. Further, a renormalon-motivated construction of the D = 0 part of the Adler function is improved in the u = 3 infrared renormalon sector, by involving the recently known information on the two principal noninteger values

k

(
j
)

=

γ

(
1
)

(

O

6

(
j
)

)

/

β

0

of the effective leading-order anomalous dimensions. Additionally, the OPE of the Adler function has now the D = 6 contribution with the principal anomalous dimension (

∼

α

s

k

(
1
)

), and terms of higher dimension (with zero anomalous dimension). Cross-checks of the obtained extracted values of α

s
and of the condensates were performed by reproduction of the (central) experimental values of several double-pinched momenta a
(2,n). The averaged final extracted values of the (

MS

¯

) coupling are:

α

s

(

m

τ

2

)
=

0.3169

−
0.0096

+
0.0070

, corresponding to

α

s

(

M

Z

2

)
=

0.1183

−
0.0012

+
0.0009

.
Using measurement uncertainties to detect incomplete assumptions about theory in an experiment with rolling marbles
Authors: Kok Karel , Priemer Burkhard
Published: February 2023

In this lab activity, carbon copy paper is used to record the horizontal distance a marble flies off a table after rolling down an incline. The minimal scatter of the dots visually shows the high precision—i.e. the small uncertainty—of the measurements to students. The theoretical prediction of this distance will be too big if students forget to include rotational energy in the energy balance when they calculate the marble’s speed at the bottom of the incline. This results in a discrepancy between the predicted horizontal distance and the measurement result. The precision of the experiment and the absence of overlap with the theoretical prediction is evidence that the prediction has to be wrong. Including rotational energy and taking a 10% energy loss due to friction into account, makes the measurement result overlap with the theoretical prediction, bringing them into agreement. Thus, measurement uncertainties guide the process of comparing the measurement result with the prediction: overlap between the theory-based prediction and the measurement result indicates agreement, whereas no overlap implies discrepancy. The lab activity presented here is an activity where measurement uncertainties are used in a meaningful, indispensable manner. The experimental result is evidence that forces students to rethink their assumptions, in this case about the conservation of energy. This leads to the revision of their calculation, emphasizing the necessity to include rotational energy and friction. Without it, the highly precise measurement result is in disagreement with the theoretical prediction. A procedure such as this—comparing empirical data with theory—is an authentic and common practice in science and should thus find its way into the physics classroom; but it cannot be done without an analysis of measurement uncertainties.
Development of fiber-based piezoelectric sensors for the load monitoring of dynamically stressed fiber-reinforced composites
Authors: Le Xuan Hung , Haentzsche Eric , Nocke Andreas , Tran Nguyen Hoai An , Kruppke Iris , Cherif Chokri
Published: February 2023

Continuous load monitoring of fiber-reinforced composites represents a complex challenge for the composite sector. In this paper, the development and characterization of piezoelectric sensors for structural health monitoring applications based on polyvinylidene fluoride (PVDF) are presented. The basic sensor structures are melt spun bicomponent filaments in a core-sheath configuration. The core is a volumetric mixture of polypropylene (PP) and Pre-Elec PP, a PP-compound modified with carbon black. The sheath is made of PVDF. Three variants with increasing volumetric Pre-Elec ratio in the core (50 vol.%, 60 vol.% and 70 vol.%) are manufactured and analyzed by conducting optical and resistance measurements as well as tensile tests. In the subsequent process step, the bicomponent filaments are braided with copper fine wires. The PP core and copper braiding of the coaxial tricomponent yarn are used as inner and outer electrode, respectively. By generating an electrostatic high voltage field between these electrodes, the PVDF interlayer is subjected to contact polarization to initialize the piezoelectric effect. The piezoelectric characteristics and thereby the sensory potential of the produced sensor yarns are quantified and analyzed on the fiber and composite scale by investigating their piezoelectric behavior during cyclic tensile tests. The results of the different sensor yarn variants are compared with each other by evaluating the measured voltage signal as a function of the induced cyclic stresses.
Drying-freeing preparation and property tests on MR fluid with MWCNTs/GO-coated CI particles
Authors: Xu Zhao-Dong , Zhou Shu , Yang Yang , Guo Ying-Qing
Published: February 2023

The traditional preparation processes for magnetorheological (MR) fluids are complicated and time-consuming, and cannot guarantee the performance of the prepared material, especially for the MR fluid with mixed coated particles. In this study, an improved drying-free preparation method of MR fluids was proposed, which adopts the magnetic separation technology to replace the traditional drying process, and an integrated preparation device for preparing MR fluids was designed on this basis to realize high efficiency and automation. The MR fluid with multiwalled carbon nanotube/graphene oxide-coated carbonyl iron particles was prepared using the designed device, and the test results showed that the drying-free preparation process can save 1/3 of the original preparation time. Then, the zero-field viscosity, yield shear stress and sedimentation rate of the prepared MR fluid were tested and compared with those prepared by the manual preparation methods. Under appropriate proportion of ingredients, the MR fluid prepared by the drying-free process has higher yield shear stress and better sedimentation stability. Therefore, the drying-free preparation process and the integrated preparation device proposed in this study are not only efficient and automated, but also can improve the performance of MR fluids.
Time-variant magnetic field, voltage, and loss of no-insulation (NI) HTS magnet induced by dynamic resistance generation from external AC fields
Authors: Zhong Zhuoyan , Wu Wei , Lu Li , Shen Boyang , Dong Fangliang , Wang Longbiao , Hong Zhiyong , Jin Zhijian
Published: February 2023

High-temperature superconducting (HTS) coils serving as DC magnets can be operated under non-negligible AC fields, like in synchronous machines of maglev trains and wind turbines. In these conditions, dynamic resistance is generated in HTS tapes, causing redistribution/bypassing of the transport current inside the no-insulation (NI) coil and its unique operational features. This issue was studied by experiments on an NI coil with DC current supply put into external AC fields. Due to the current redistribution induced by dynamic resistance, the central magnetic field and voltage of the NI magnet initially undergo various transient processes, and eventually exhibit a stable central magnetic field reduction and a DC voltage. These time evolutions have implications for the time-varying torque and loss of an HTS machine. These time evolutions are strongly affected by the contact resistivity distribution, and whether it is the first time that the NI magnet has been exposed to the AC field, showing several qualitatively different waveforms (e.g. some are even non-monotonic with time). The magnitudes of the stable central field reductions, and their observed linear correlation with the DC voltages are found to be decided by the local contact resistivity of the innermost and outermost several turns. It is also noted that the non-insulated turn-to-turn contact help lessening the loss induced by the dynamic resistance. A numerical model is established to analyze/explain these experimental results by observing the microscopic current distribution. Two risks of quench are noticed: (i) the azimuthal current of the middle part turns increases as the AC field is applied; (ii) a concentration of radial current is observed near the terminals of the NI coil.
On the uniqueness of Einstein-Cartan theory: Lagrangian, covariant derivative and equation of motion
Authors: Chen Zi-Wei , Diao Run , Chen Xiang-Song
Published: February 2023

In the standard Einstein-Cartan theory, matter fields couple to gravity through the Minimal Coupling Procedure (MCP), and yet leave the theory an ambiguity. Applying MCP to the action or to the equation of motion would lead to different gravitational couplings. We propose a new covariant derivative to remove the ambiguity and discuss the relation between our proposal and previous treatments on this subject.
Calibration of GNSS stations for UTC
Authors: Petit Gérard , Defraigne Pascale
Published: February 2023

Global navigation satellite system (GNSS) time transfer has been used for four decades in the generation of universal time coordinated (UTC), starting with GPS in the 1980s. Calibration of GNSS receivers is then essential to ensure that time links used in UTC are accurate and remain stable with time. In this paper we study the different calibration schemes based on relative calibration of GNSS receivers that have been operated to fulfill these goals. We specially focus on the current calibration scheme in operation since 2014 and based on a collaboration between the BIPM and the Regional Metrology Organizations. We show that the achieved accuracy and long-term stability of calibration results, thus of UTC time links, are well in line with the stated uncertainties. We study an extended set of absolute calibration results and show that they complete and validate the BIPM scheme, and that relative calibration is still the essential tool to ensure accurate time links for UTC.
Wind Speed Power Data Cleaning Method for Wind Turbines Based on Fan Characteristics and Isolated Forests
Authors: Lai Gang , Liao Li , Zhang Liang , Li TianYi
Published: February 2023

To address the situations that wind turbine operating conditions are complex and variable, the wind speed and power data are confusing, and there are many anomalies with significant differences, which make data analysis difficult, a method of cleaning wind speed and power data of wind turbines based on turbine characteristics and isolated forests is established. Firstly, the wind turbine power data is initially screened with the actual wind turbine characteristics. Then, isolated trees are constructed based on the initial filtered data. Afterward, the built isolated trees are used to calculate the power anomalies to be cleaned and to distinguish the anomalies, which finally achieves effective and efficient data cleaning. The experimental analysis results with the actual unit data of a wind farm show that this method is more efficient and more general than that of the traditional cleaning methods.
Embedded-based Thermal Expansion Meter Test System Design
Authors: Liu Yutao , Yang Shifeng , Shui Guang
Published: February 2023

In order to realize the intelligent test of thermal expansion, the overall design scheme of the thermal expansion test system is given, the test platform of the thermal expansion test system is constructed, and the single-neuron PID control algorithm is used to control the heating rate of the electric furnace by using the microcontroller, the upper computer software is written by using Python, the data transmission between the upper computer and the microcontroller is made through the software, and the real-time acquisition of temperature and displacement signals is realized. The software enables data transfer between the upper computer and the microcontroller, real-time acquisition, storage, and analysis of temperature and displacement signals, and it is able to meet the requirements of practical engineering tests.
Low-carbon Electricity Consumption Mechanism Considering the Interaction and Coordination of Source and Charge
Authors: Xu Hezhong , Xu Mingfeng , Hui Chengxuan , Lv Zeming , Liu Zhiping , Wang Mingyu , Weng Xiaochong
Published: February 2023

With the increasing shortage of traditional energy and environmental pollution, the “double carbon” goal was put forward. The construction of a new power system is an important way to achieve this goal, and how to maximize the consumption of new energy under the interaction and coordination of source and charge is the focus of this paper. Through discussing the new development trend of the present situation in the construction of electric power systems and the source charge interaction, the theoretical foundation is established to promote low-carbon electricity given the source of the collaborative optimization model. Then, the power grid company’s profit is maximized by considering the source charge interactive coordination. Finally, the process is optimized to establish the objective function and variables of the scope of the restrictions, so as to ensure the improvement and construction of the low-carbon electricity consumption mechanism.
Distribution network reconfiguration control and protection method based on multi-source data interaction
Authors: Yu Zhihao , Shou Shaoan , Wang Yuanxing , Wang Dengqing , Lu Xiang , Ma Chunsheng
Published: February 2023

Distribution network reconfiguration technology is the key technology of distribution network fault treatment and power supply recovery. Given the problem that the traditional distribution network reconfiguration algorithm needs a lot of power flow calculation and low efficiency to find the optimal target, the simulated annealing algorithm is proposed to optimize the computing speed and searching ability of the distribution network reconfiguration algorithm. Firstly, the information interaction technology of distribution network protection and control equipment is studied, and the real-time data rapid peer-to-peer exchange and data and information interaction model is built, which improves the fault detection and timely removal ability of the distribution network. Secondly, the simulated annealing algorithm is used to reduce the number of power flow calculations, reduce the calculation time, improve the calculation speed of network reconstruction problems, and ensure that the optimal or better network topology can be obtained. Finally, the simulation analysis of the IEEE37 node system verifies the effectiveness of the proposed reconfiguration protection method in a complex environment with massive access to distributed energy.
Separation of Urban Substation Noise and Environmental Noise based on Independent Component Analysis
Authors: Xu Luwen , Qiu Ni , Yang Bo , Peng Shiwei
Published: February 2023

With the development of urbanization, substations have started to be established in urban areas where the population is concentrated. To realize effective control of the substation noise, accurate measurements of the noise inside the substation and the surrounding area are necessary. However, in an urban area, the background noise, such as traffic noise, causes the sampled signals to contain not only the substation noise but also the background noise, which decreases the measurement accuracy. Thus, separating the substation noise from the environmental background noise is necessary. An independent component analysis method is used to realize the separation of the substation noise from complex environmental noises. In this paper, two typical environmental noises are selected, and their characteristics and the urban substation noise are analyzed. Then, a separation method based on the independent component analysis is constructed for separating substation noise. Its accuracy is evaluated using measured mixed signals. The verification shows that the separated substation noise is very close to the original substation noise signal, which shows that the method can be used in practical substation noise control engineering applications.
Study on voltage stability considering unified power flow controller
Authors: Hu Yuan , Wu Peng , Hou Zhaojun , Wang Ning , Zhang Shuai , Li Yan , Zhao Penghui , Gao Ming , Li Tianhao
Published: February 2023

The access of the unified power flow controller (UPFC) can better meet the requirements of new power system construction with a high proportion of non-fossil energy and large-scale access, and it is more intelligent than the traditional control mode. Through the sensitivity analysis of the Jacobian matrix, the voltage stability of the power system before and after the access to the unified power flow controller is compared, and the simulation analysis in MATLAB/PSAT environment is adopted to simulate the IEEE9-bus system, showing that the access of UPFC achieves the effect of flexible control and can effectively improve the voltage stability of the system.
Differentiated Configuration Options for Centralized and Distributed Energy Storage
Authors: Gao Xuefeng , Xu Yueyang , Liu Yuchun , Li Hao , Wang Xinhong , Wang Dong , Shi Yu
Published: February 2023

With the rapid development of new energy power generation technology and the promotion and application of energy storage in smart grids, energy storage is more and more favored by people. Firstly, the energy storage technology is classified, and its role in the power grid is analyzed. Then, the economy of centralized and distributed energy storage is analyzed. Further, according to the technical and economic characteristics of centralized energy storage and distributed energy storage, the applications of these two types of energy storage are introduced. Finally, based on the characteristics of renewable energy in Jilin Province, recommendations are made for the placement of energy storage in Jilin Province in the context of “carbon neutrality and carbon peaking.”
Research on key technologies of multi-core DSP in smart substation redundancy network testing
Authors: Tang Taonan , Sun Bolong , Li Zhonglei , Yang Minghua , Yi Shuwei , Wang Yibo
Published: February 2023

Aiming at the network characteristics of a smart substation redundant network with complex communication messages, a large amount of interactive data, and high real-time performance, the test model of multiple submachines in a High-Availability Seamless Redundancy (HSR) loop network is analyzed. The requirements of packet types, size, and transmission speed are evaluated, and a hardware solution based on a multi-core Digital Signal Processor (DSP) and Parallel architecture FPGA is designed. The multi-core interaction strategy of DSP software and the multi-port high-speed communication method of FPGA are proposed, and the inter-core communication (IPC) interrupts and shared memory to achieve fast data migration between cores, based on the Serial RapidIO (SRIO) to complete high-speed message transmission. The throughput, delay, packet loss rate, and error frame detection functions are realized, tested, and verified, providing theoretical and practical support for the evaluation of redundant network performance of smart substations.
Design of honeysuckle harvesting robot based on MBSE and TRIZ
Authors: Liu Wenyue , Du Xinyue , Fu Mengyu , Gao Guohua
Published: February 2023

The design of field operation robots is a complex and comprehensive task. The external environment that changes at any time imposes strict requirements on the design. In this paper, we propose a systematic and innovative design of a honeysuckle harvesting robot using MBSE and TRIZ methods, deeply excavating the potential failure factors in 5M1E and effectively completing the robot design task through requirements analysis, functional modeling, and architecture design to ensure the integrity and comprehensiveness of the process.
Design and Optimization of 4-bit Absolute-value Detector Based on CMOS
Authors: Jia Yu
Published: February 2023

With the development of neural signal acquisition systems, spike-sorting algorithms have been paid full attention. As one of the most extensively used spike-detection algorithms, a 4-bit absolute-value detector is designed in the paper, which comprises three types of architecture. The first design is using combinational logic circuit through a truth table of the absolute value of 2′s complement format and a comparator; the second design is a combination of a series of half adders and transmission gates and a comparator; the third design consists of a combinational logic circuit by truth table of 2′s complement and a cascade of full adders. Then the paper compares the total number of stages and consuming transistors of each circuit, and finally chooses the second circuit, which has five stages and 74 transistors of consumption, as the object of following optimization of critical path delay and energy consumption. With gate sizing, the optimized critical path delay is about 43.05 tp0. The original energy consumption under minimum delay is 49.88C, and the optimized energy consumption under 1.5x minimum delay is 30.35C which is reduced by 39.16%. The processing of the functional realization and circuit optimization of absolute-value detectors can both benefit from the design presented in this work.
A Low Energy Depletion CMOS Transistor-based 4-bit Absolute-value Detector
Authors: Du Chenyu , Guo Yucheng , Zhang Junchao
Published: February 2023

With the development of the electronic industry, the requirements for equipment are becoming higher and higher in recent years. In this paper, a 4-bit absolute value detector is designed to have a low delay and energy consumption. The detector is composed of MUX, an adder, and a comparator. By comparing the 4-bit input with the given threshold value, the result is output. Based on the logic effort theory, this paper calculates the logic effort and parasitic delay of each stage of the detector and uses the transmission gate logic to redesign the XOR gate, which greatly improves its performance. Through certain calculations and optimization, the delay and energy consumption of the detector is reduced. Finally, this paper realizes a relatively simple 4-bit absolute value detection circuit, which has a small number of transistors and greatly improves the performance of the circuit. At the same time, it has a certain reference value for the related circuit design.