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Connections Between Induction Generator Effect and Open-loop Modal Proximity to Cause Sub-synchronous Oscillations in Series-compensated Power System

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 963-973页

作者： Wenjuan Du Yang Wang H.f.Wang Tao Zhao Tim Littler College of Electrical Engineering Sichuan UniversityChengduChina School of Electrical Engineering the Queen’s University of BelfastBelfastUK IEEE

The induction generator effect(IGE)and the openloop modal proximity(OLMP)are two different reasons why subsynchronous oscillations(SSOs)in a series-compensated power system(SCPS)may *** IGE attributes the growing SSOs to negative resistance,while the OLMP explains the SSO mechanism from the standpoint of modal *** this paper,we investigate the connections between the IGE and the OLMP through equivalent RLC circuit and open-loop modal *** investigation is conducted for two types of seriescompensated power systems where either a synchronous generator or a DfIG is connected at the sending *** investigation reveals the conditions,in which the IGE and the OLMP may jointly cause the growing SSOs,i.e.,both the IGE and the OLMP can explain why the growing SSOs ***,the investigation indicates that the IGE and the OLMP may be totally irrelevant and lead to growing SSOs *** implies that it is possible that in a SCPS,the growing SSOs are only due to the IGE,and the OLMP is non-existent,and vice ***,when the growing SSOs occurs in a SCPS,examination based on both the IGE and the OLMP should be carefully conducted in order to find if the oscillatory instability is due to the IGE,or the OLMP,or both of them.

关键词： Induction generator effect open-loop modal proximity series compensation sub-synchronous oscillations

All-electron basis sets for H to Xe specific for ZORA calculations:Applications in atoms and molecules

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Chinese Physics B 2024年第8期33卷 238-246页

作者： C.S.Gomes f.E.Jorge A.Canal Neto Departamento de fisica Universidade Federal do Espirito Santo29075-910 VitoriaESBrazil Departamento de fisica Instituto de Ciencias Exatas e BiologicasUniversidade Federal de Ouro Preto Campus Universitario Morro do Cruzeiro35402-136 Ouro PretoMGBrazil

A segmented basis set of quadruple zeta valence quality plus polarization functions(QZP)for H through Xe was developed to be used in conjunction with the ZORA *** set was augmented with diffuse functions to describe electrons farther away from the nuclei *** the ZORA-CCSD(T)/QZP-ZORA theoretical model,atomic ionization energies and bond lengths,harmonic vibrational frequencies,and atomization energies of some molecules were *** addition of core-valence corrections has been shown to improve the agreement between theoretical and experimental results for molecular *** atomization energies,a similar observation emerges when considering spin-orbit *** the augmented QZP-ZORA set,static mean dipole polarizabilities of a set of atoms were calculated and compared with previously published recommended and experimental *** evaluations of the ZORA and Douglas–Kroll–Hess Hamiltonians were made for each property studied.

关键词： QZP-ZORA and AQZP-ZORA basis sets elements from H to Xe CCSD(T)method atomic and molecular properties

Radiative loss of coherence in free electrons:a long-range quantum phenomenon

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Light(Science & Applications) 2024年第2期13卷 294-301页

作者： Cruz I.Velasco Valerio Di Giulio f.Javier García de Abajo ICfO-Institut de Ciencies fotoniques The Barcelona Institute of Science and Technology08860Castelldefels(Barcelona)Spain ICREA-InstitucióCatalana de Recerca i Estudis Avançats Passeig Lluís Companys 2308010BarcelonaSpain

Quantum physics rules the dynamics of small objects as they interact over microscopic length ***,quantum correlations involving macroscopic distances can be observed between entangled photons as well as in atomic gases and matter waves at low *** long-range nature of the electromagnetic coupling between charged particles and extended objects could also trigger quantum phenomena over large ***,we reveal a manifestation of quantum mechanics that involves macroscopic distances and results in a nearly complete depletion of coherence associated with which-way free-electron interference produced by electron-radiation coupling in the presence of distant extended *** is a ubiquitous effect that we illustrate through a rigorous theoretical analysis of a two-path electron beam interacting with a semi-infinite metallic plate and find the inter-path coherence to vanish proportionally to the path separation at zero temperature and exponentially at finite *** investigated regime of large distances originates in the coupling of the electron to radiative modes assisted by diffraction at material structures but without any involvement of material *** the fundamental interest of this macroscopic quantum phenomenon,our results suggest an approach to measuring the vacuum temperature and nondestructively sensing the presence of distant objects.

关键词： temperature quantum macroscopic

Metallurgical Microstructure Complexity in the Electron Beam Welding (EBW) Joint of Ti6246

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Journal of Minerals and Materials Characterization and Engineering 2024年第2期12卷 100-111页

作者： Daniel moreno Yohanan Nachmana Roei Saraga Tal Rokah Denis Panchenco Michael Mansano Elinor Itzhaky Moshe Shapira Beth Shemesh Engines LTD FAA & EASA Beth Shemesh Israel

Electron Beam Welding (EBW) is employed to both melt and unite materials, influencing their thermal history and subsequently determining the microstructure and properties of the welded joint. Welding Titanium alloys involves undergoing local melting and rapid solidification, subjecting the material to thermal stresses induced by a thermal expansion coefficient of 9.5 × 10 m/m°C. This process, reaching range temperatures from the full melting alloy to room temperature, results in phase formation dictated by the thermodynamic preferences of the alloyed elements, posing a significant challenge. Recent efforts in simulation and calculations have been undertaken elsewhere to address this challenge. This study focuses on a joint of two plates with differing cross-sectional areas, influencing heat transfer during welding. This report presents a case study focusing on the metallurgical changes observed in the microstructure within the welded zone, emphasizing alterations in the cooling rate of the welded joint. The investigation utilizes optical metallography, Vickers’s Hardness testing, and SEM (scanning electron microscopy) to comprehensively characterize the observed changes in addition to heat transfer simulation of the welded zone.

关键词： Ti Alloys Welding Phase formation Hardness Metallography

Application of novel constrained friction processing method to produce fine grained biomedical Mg-Zn-Ca alloy

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Journal of Magnesium and Alloys 2024年第2期12卷 516-529页

作者： Ting Chen Banglong fu Junjun Shen Uceu f.H.R.Suhuddin Björn Wiese Yuanding Huang Min Wang Jorge f.dos Santos Jean Pierre Bergmann Benjamin Klusemann Solid State Materials Processing Institute of Material MechanicsHelmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany functional Magnesium Materials Institute of Metallic BiomaterialsHelmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany Shanghai Key Laboratory of Materials Laser Processing and Modification Shanghai Jiao Tong UniversityDongchuan Road 800Shanghai 200240China Applied Materials and Manufacturing Energy and Environment DivisionPacific Northwest National LaboratoryPO Box 999RichlandWA 99352USA Production Technology Group Technisiche Universität IlmenauGustav-Kirchhoff-Platz 2Ilmenau 98693Germany Institute for Production Technology and Systems Leuphana University of LüneburgUniversitätsallee 1Lüneburg 21335Germany

In order to obtain Mg alloys with fine microstructures and high mechanical performances,a novel friction-based processing method,name as“constrained friction processing(CfP)”,was *** CfP,defect-free Mg-Zn-Ca rods with greatly refined grains and high mechanical properties were *** to the previous as-cast microstructure,the grain size was reduced from more than 1 mm to around 4μm within 3 s by a single process *** compressive yield strength was increased by 350%while the ultimate compressive strength by 53%.According to the established material flow behaviors by“tracer material”,the plastic material was transported by shear *** the base material to the rod,the material experienced three stages,*** by the tool,upward flow with additional tilt,followed by upward *** microstructural evolution was revealed by“stop-action”*** microstructural development at regions adjacent to the rod is mainly controlled by twinning,dynamic recrystallization(DRX)as well as particle stimulated nucleation,while that within the rod is related to DRX combined with grain growth.

关键词： Constrained friction processing Magnesium alloys Microstructure Mechanical properties Grain refinement Plastic deformation

failure to Rescue as a Quality Metric in Congenital Heart Surgeries in a High-Complexity Service Provider Institution Located in a Middle-Income Country

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Congenital Heart Disease 2024年第2期19卷 207-218页

作者： Gustavo Cruz Santiago Pedroza Juan f.Vélez Jessica Largo Juan f.Tejada Jorge H.Mejía-Mantilla Departamento de Anestesiología Fundación Valle del LiliCali760032Colombia Centro de Investigaciones Clínicas Fundación Valle del LiliCali760032Colombia Departamento de Cardiología Pediátrica Fundación Valle del LiliCali760032Colombia facultad de Medicina Universidad IcesiCali760031Colombia Unidad de Cuidado Intensivo Fundación Valle del LiliCali760032Colombia

Background:failure to rescue has been an effective quality metric in congenital heart ***,mor-bidity and mortality depend greatly on non-modifiable individual factors and have a weak correlation with better-quality *** aim to measure the complications,mortality,and risk factors in pediatric patients undergoing congenital heart surgery in a high-complexity institution located in a middle-income country and compare it with other institutions that have conducted a similar ***:A retrospective observational study was conducted in a high-complexity service provider institution,in Cali,*** pediatric patients undergoing any congenital heart surgery between 2019 and 2022 were *** main outcomes evaluated in the study were complication,mortality,and failure to rescue *** and multivariate logistic regression analysis was performed with mortality as the outcome ***:We evaluated 308 congenital heart *** the outcomes,201(65%)complications occurred,23(7.5%)patients died,and the fTR of the entire cohort was 11.4%.The presence of a postoperative complication(OR 14.88,CI 3.06–268.37,p=0.009),age(OR 0.79,CI 0.57–0.96,p=0.068),and urgent/emergent surgery(OR 8.14,CI 2.97–28.66,pficant variables in predicting ***:failure to rescue is an effective and comparable quality measure in healthcare institutions and is the major contributor to postoperative mortality in congenital heart *** our higher mortality and complication rate,we obtained a comparable failure to rescue rate to high-income countries’health institutions.

关键词： Congenital heart surgery complication mortality failure to rescue quality metric

Niche differentiation among facultative filter feeders: Insights from invasive Ponto-Caspian mysids

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Current Zoology 2024年第4期70卷 513-521页

作者： Péter Borza Varsha Rani Csaba f.Vada Institute of Aquatic Ecology Centre for Ecological ResearchKarolina ut 29.1113 BudapestHungary Doctoral School of Biology Institute of BiologyEotvos Lorand UniversityPazmany Péter sétany 1/C1117 BudapestHungary

The degree of dietary specialization has a fundamental impact on the ecological function and interactions of suspension *** niche differentiation by food particle size is common among obligate suspension feeders,its role is not evident in facultative *** this study,we aimed at providing new insights on the matter by focusing on sympatric mysid *** mysids use different mechanisms for raptorial and filter-feeding,they represent a more adequate model system than for example,the more extensively studied *** made morpholog-ical measurements on the 4 coexisting invasive Ponto-Caspian mysid species to determine the areas and mesh sizes of their *** also quantified their clearance rates on the microalga Cryptomonas *** a laboratory experiment to reveal how morphological differences manifest in their overall filtering *** found relatively small but consistent differences in the primary filter area among the species,indicating that morphological constraints due to the enclosed position of the setae might limit the possibility for *** primary filter mesh sizes were small in all 4 species(0.69-2.73μm)with moderate but consistent intraspecific differences,suggesting that the benefit of being able to capture small particles might outweigh the pressure for *** observed clearance rates were in accordance with the morphological characteristics of the species,highlighting that auxiliary filters(present in one of the species,Limnomysis benedeni)are needed to increase filtering capacity *** study confirmed that food particle size can contribute to the niche differentiation of facultative filter feeders,but also indicated that they can tolerate a higher overlap than obligate *** observed differences were related to the habitat preferences and predatory potentials of the species,suggesting that complementarity among the different niche axes might further facilitate theircoexistence.

关键词： clearance rate coexistence filter area filtermesh size.

Tuning the optoelectronic properties for small organic compounds as organic solar cell applications

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Optoelectronics Letters 2024年第7期20卷 412-417页

作者： Hussein K.Mejbel Lafy f.Al-Badry Department of Physics College of Education for Pure ScienceUniversity of Thi-QarNassiriya 64001Iraq Department of Physics College of ScienceUniversity of Thi-QarNassiriya 64001Iraq1

Recently,organic solar cells have attracted the attention of many researchers owing to flexibility,low cost,light weight and large-area applications,and significant improvement in the power conversion efficiency(PCE).In this work,we designed chains from organic compounds as donors and replaced the core unit in each series with a variety of acceptors in order to enhance their optical and electronic characterization and performance for power conversion efficiencies in organic solar *** utilized density functional theory(DfT)and time-dependent density functional theory(TD-DfT)to investigate the geometry optimization by using the Gaussian 09 *** electronic and optical properties were determined,which involve the lowest unoccupied molecular orbital(LUMO)and the highest occupied molecular orbital(HOMO)levels,the band gap energy,maximum absorption wavelength(λ_(max)),open circuit voltage(V_(oc)),and light harvesting efficiency(LHE).Our evaluation denotes that the small compounds suggested are predicted to exhibit the best performance compared to the first series(SC1),like a lower band gap energy,a lower HOMO energy level,a greater absorption range,and a larger PCE.

关键词： orbital occupied compounds

Adsorption of yttrium(Y^(3+)) and concentration of rare earth elements from phosphogypsum using chitin and chitin aerogel

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Journal of Rare Earths 2024年第4期42卷 775-782页

作者： Glaydson S.dos Reis Diana Pinto Sabrina f.Lütke Eder C.Lima Luis f.O.Silva Irineu A.S.De Brum Guilherme L.Dotto Department of forest Biomaterials and Technology Biomass Technology Centre Swedish University of Agricultural SciencesUmeaE13Swedn Universidad De La Costa Calle 58#55-66080002BarranquillaAtlanticoColombia Research Group on Adsorptive and Catalytic Process Engineering(ENGEPAC) Federal University of Santa MariaAv.Roraima100079705900Santa MariaRSBrazil Institute of Chemistry Federal University of Rio Grande do Sul90040060Porto AlegreBrazil

Chitin powder and chitin-aerogel were prepared from shrimp wastes and used to uptake Y^(3+)from aqueous solutions and concentrate this rare earth element from phosphogypsum(PG).Chitin aerogel displays a specific surface area of 945 m^(2)/g,while chitin powder is 3.6 m^(2)/g,which largely influences its adsorption *** the adsorption in synthetic solutions,the effect of pH on Y^(3+)removal is strong for chitin powder *** contrast,no big pH influence was detected for chitin *** interactions and chelation can highlight the proposed mechanism of Y^(3+)on chitin adsorbents for the powder and ***,in addition to these interactions,pore filling/pore diffusion is the main mechanism of Y^(3+)removal in the chitin *** aerogel is efficient in concentrating 8 times the Y^(3+)from PG,a very complex *** complex chitin aerogel-Y^(3+)can be a secondary source of rare earth elements for other applications.

关键词： Rare earths Sustainable material Chitin powder Chitin porous aerogel Yttrium adsorption and recovery