bluuebunny/crossref_metadata_2025 huggingface dataset:
Separation and extensive evaluation of properties of fuel and non-fuel portions of pyrolytic bio-oil obtained from Erythrina indica biomass
Authors: Ahmed Gaffer , Kishore Nanda
Published: May 2023

Pyrolytic conversion of Erythrina indica under inert conditions at 600 °C and 1 bar pressure resulted in 26.873 wt. % of bio-oil, 42.870 wt. % of biochar, and 30.257 wt. % of non-condensable gases. The fuel phase separation was performed at 10%, 20%, 30%, and 40% (on volume basis) of a solvent-to-bio-oil ratio using dichloromethane and n-hexane, which depicted significant improvement in its physiochemical properties. However, the fuel phase obtained using n-hexane had better physiochemical properties than that obtained by dichloromethane, indicating n-hexane as a better solvent. The fuel phase extraction utilizing 30 and 40 vol. % of n-hexane showed that they were close to regular gasoline in terms of density, viscosity, and calorific value, which turned out to be the best accomplishment of this work. The calorific value of the fuel phases, extracted by dichloromethane and n-hexane, respectively, were discovered to range between 14.360 and 23.670 MJ/kg and 26.290 and 39.730 MJ/kg. Gross calorific values of corresponding biochar and the non-condensable gases were found to be 28.030 MJ/kg and 14.486 MJ/N m3, respectively. The composition of non-condensable gases revealed that 16.822 vol. % of hydrogen is present, and thus, it can be a good source of green hydrogen. Biochar produced from the pyrolytic conversion of E. indica is equivalent to conventional coal based on comparison of their physical, fuel, and other relevant properties.
Data-driven system identification of hydrodynamic maneuvering coefficients from free-running tests
Authors: Chillcce Guillermo , el Moctar Ould
Published: May 2023

A data-driven system identification approach was developed to identify the hydrodynamic coefficients of a mathematical maneuvering model. The method, developed primarily for use in the context of autonomous shipping, solved the ship motion equations using measurements from free-running model tests, whereby an efficient recently developed Euler equation-based numerical approach determined the zero-frequency added masses. The method is simple and robust and incorporates the physical properties of hydrodynamic forces to enforce a physically realistic solution. The method was verified and validated with free-running maneuver tests. The predicted ship kinematics and trajectories compared favorably with the measurements. The potential of the method was demonstrated.
Experimental study on the startup of the annular wick type heat pipe using fiber optical temperature measurement technique
Authors: Hassan Yassin A.
Published: May 2023

This study used optical fiber-distributed temperature sensors to measure the internal and external temperature distributions of a water-cooled heat pipe. The sensor technology used in this study is fiber optical distributed temperature sensing, a distributed sensing technique based on the naturally occurring Rayleigh backscatter in optical fibers. This measurement technique provides maximum spatial resolution for static and semi-static applications. Using this sensor, the temperature distribution of the heat pipe's internal, external, vapor core, and the wick was measured with a spatial resolution of 0.65 mm, a sampling frequency of 40 Hz, and a temperature resolution of 0.1 °C. Through the measured temperature distribution database, the starting phenomenon, the effective length trend, and the limitation onset were observed. From the results, it is found that a high-temperature peak appears at the evaporator if a high initial power (75 W) is imposed on the heat pipe, even after the heat pipe approaches the normal operating status. The peak is not observed in a slower startup (30 W initial power then slowly increased to 75 W). It is also found that the temperature distributions and effective condenser length of the heat pipe highly depend on the cooling conditions. There are variations in the temperature according to the radial direction of the horizontal heat pipe due to gravity. Lead and lag of the temperature evolution were observed at the onset of the operating limitations.
Microstructure and adsorption characteristics of Zr–Co–RE getter films deposited using krypton as sputtering gas
Authors: Zhou Chao , Li Detian , He Yanchun , Ma Zhanji , Yang Lamaocao
Published: May 2023

The vacuum level in micro-electro-mechanical system devices needs to be achieved and maintained using non-evaporable getter film technology. Zr–Co–RE getter films are deposited by direct current (DC) magnetron sputtering using krypton (Kr) as the sputtering gas. The influence of sputtering gas pressure and DC sputtering power on the microstructure and adsorption characteristics of films is investigated. Zr–Co–RE films deposited at different gas pressures all grow in a columnar shape. Films grown at low Kr pressures are relatively dense and have a structure with fewer cracks, whereas high Kr pressures result in a uniform cluster and columnar structure with more gaps and micro-cracks. In addition, it is revealed that DC sputtering power has great influence on the film structure and adsorption performance. The films deposited at low sputtering power contain more micro-cracks, which are distributed uniformly. At high sputtering power, the cluster structure is not obvious. Consequently, high Kr pressures and low sputtering power are beneficial to improve the adsorption performance. Hydrogen adsorption tests are carried out using a special vacuum system, keeping the pressure constant. The highest initial adsorption speed is 89 (ml/s)/cm2, obtained at 4.0 Pa Kr pressure and 300 W sputtering power. Meanwhile, the Zr–Co–RE films deposited under these conditions have excellent adsorption stability.
Geospatial distribution of tertiary hospitals across Australian cities
Authors: Baazeem Mazen , Kruger Estie , Tennant Marc
Published: May 2023

Objective This study aimed to map the geographic distribution of tertiary hospitals in Australia’s most populous cities. Good access to hospital facilities improves the health and welfare of a community. The use of geographic information system (GIS) technology can assist in understanding spacial accessibility to services. Methods Using Quantum GIS, a geodatabase was constructed to incorporate hospital locations and demographic distribution data throughout Australia’s 20 most populous cities. Data on the population’s age groups were integrated into the geodatabase to investigate the distribution of age groups and their utilisation of access to emergency departments in tertiary public health care. Overall this study reported the geospatial distribution of 89 tertiary hospitals and the demographics of the population in areas around these hospitals. Results The majority of hospitals were located in the three most populated cities of New South Wales (NSW), Sydney, Wollongong and Newcastle, which contain a total of 32 hospitals, with 23 (72%) of the hospitals in Sydney. There were 7.8, 24.0, 53.4 and 81.0% of the population in NSW within 1.5, 3, 6 and 50 km of the hospitals, respectively. The second-highest number of hospitals was in Victoria (n = 22), with 18 (82%) hospitals located in Melbourne. This was followed by Queensland (n = 14), with eight (57%) hospitals located in Brisbane. Conclusions The results indicate that 82.2% of the Australian population lives within a 50 km radius of a tertiary hospital, with NSW having higher age distribution percentages than the other states. The results of this study could be used to locate and improve areas of need with a high burden of disease and low accessibility to healthcare services.
Copper exposure leads to changes in chlorophyll content and secondary metabolite profile in Lantana fucata leaves
Authors: Pivetta Carlise Patrícia , Chitolina Samuel Francisco , Dartora Nessana , Pelegrin Carla Maria Garlet de , Santos Marlei Veiga dos , Cassol Fabiano , Batista Laura Spohr
Published: May 2023

Cultivation of plants in environments polluted by metals at toxic levels can affect the biosynthesis of secondary metabolites. Here, we analysed the effect caused by excess copper on the concentration of chlorophylls a and b and the profile of secondary metabolites of Lantana fucata leaves. Five copper (Cu) treatments (mg Cu kg−1 soil) were tested: T0, 0; T1, 210; T2, 420; T3, 630; and T4, 840. We found that the concentrations of chlorophylls in the plants decreased when compared to the control. However, this did not lead to a significant reduction in its growth, possibly due to the low translocation of the metal to shoots and the activation of plant defence systems to tolerate the environment in which they are exposed, increasing the emission of lateral roots and activating pathways for the production of secondary metabolites. Therefore, we found a decrease in the concentration of two key compounds in secondary metabolism, p-coumaric and cinnamic acids in treatments with higher copper concentrations. We also found an increase in phenolics. Decreases in p-coumaric and cinnamic acids may have occurred because these are precursors in the synthesis of phenolic compounds, which are increased in the high Cu treatments. Six secondary metabolites were characterised, described for the first time for this plant species. Thus, the presence of excess Cu in the soil may have triggered an increase in the amount of reactive oxygen species in the plants, which that led to the synthesis of antioxidant compounds, as a defence strategy.
Two superconducting states with broken time-reversal symmetry in FeSe

1−
x

S

x
Authors: Matsuura Kohei , Roppongi Masaki , Qiu Mingwei , Sheng Qi , Cai Yipeng , Yamakawa Kohtaro , Guguchia Zurab , Day Ryan P. , Kojima Kenji M. , Damascelli Andrea , Sugimura Yuichi , Saito Mikihiko , Takenaka Takaaki , Ishihara Kota , Mizukami Yuta , Hashimoto Kenichiro , Gu Yilun , Guo Shengli , Fu Licheng , Zhang Zheneng , Ning Fanlong , Zhao Guoqiang , Dai Guangyang , Jin Changqing , Beare James W. , Luke Graeme M. , Uemura Yasutomo J. , Shibauchi Takasada
Published: May 2023

Iron-chalcogenide superconductors FeSe

1−
x

S

x

possess unique electronic properties such as nonmagnetic nematic order and its quantum critical point. The nature of superconductivity with such nematicity is important for understanding the mechanism of unconventional superconductivity. A recent theory suggested the possible emergence of a fundamentally new class of superconductivity with the so-called Bogoliubov Fermi surfaces (BFSs) in this system. However, such an ultranodal pair state requires broken time-reversal symmetry (TRS) in the superconducting state, which has not been observed experimentally. Here, we report muon spin relaxation (
μ
SR) measurements in FeSe

1−
x

S

x

superconductors for
0
≤
x
≤
0.22
covering both orthorhombic (nematic) and tetragonal phases. We find that the zero-field muon relaxation rate is enhanced below the superconducting transition temperature
T
c
for all compositions, indicating that the superconducting state breaks TRS both in the nematic and tetragonal phases. Moreover, the transverse-field
μ
SR measurements reveal that the superfluid density shows an unexpected and substantial reduction in the tetragonal phase (
x
>
0.17
). This implies that a significant fraction of electrons remain unpaired in the zero-temperature limit, which cannot be explained by the known unconventional superconducting states with point or line nodes. The TRS breaking and the suppressed superfluid density in the tetragonal phase, together with the reported enhanced zero-energy excitations, are consistent with the ultranodal pair state with BFSs. The present results reveal two different superconducting states with broken TRS separated by the nematic critical point in FeSe

1−
x

S

x

, which calls for the theory of microscopic origins that account for the relation between nematicity and superconductivity.
Imaging the subcellular viscoelastic properties of mouse oocytes
Authors: Flé Guillaume , Van Houten Elijah , Rémillard-Labrosse Gaudeline , FitzHarris Greg , Cloutier Guy
Published: May 2023

In recent years, cellular biomechanical properties have been investigated as an alternative to morphological assessments for oocyte selection in reproductive science. Despite the high relevance of cell viscoelasticity characterization, the reconstruction of spatially distributed viscoelastic parameter images in such materials remains a major challenge. Here, a framework for mapping viscoelasticity at the subcellular scale is proposed and applied to live mouse oocytes. The strategy relies on the principles of optical microelastography for imaging in combination with the overlapping subzone nonlinear inversion technique for complex-valued shear modulus reconstruction. The three-dimensional nature of the viscoelasticity equations was accommodated by applying an oocyte geometry-based 3D mechanical motion model to the measured wave field. Five domains—nucleolus, nucleus, cytoplasm, perivitelline space, and zona pellucida—could be visually differentiated in both oocyte storage and loss modulus maps, and statistically significant differences were observed between most of these domains in either property reconstruction. The method proposed herein presents excellent potential for biomechanical-based monitoring of oocyte health and complex transformations across lifespan. It also shows appreciable latitude for generalization to cells of arbitrary shape using conventional microscopy equipment.
Urban effects on local cloud patterns
Authors: Vo Thuy Trang , Hu Leiqiu , Xue Lulin , Li Qi , Chen Sisi
Published: May 2023

Urbanization extensively modifies surface roughness and properties, impacting regional climate and hydrological cycles. Urban effects on temperature and precipitation have drawn considerable attention. These associated physical processes are also closely linked to clouds’ formation and dynamics. Cloud is one of the critical components in regulating urban hydrometeorological cycles but remains less understood in urban-atmospheric systems. We analyzed satellite-derived cloud patterns spanning two decades over 447 US cities and quantified the urban-influenced cloud patterns diurnally and seasonally. The systematic assessment suggests that most cities experience enhanced daytime cloud cover in both summer and winter; nocturnal cloud enhancement prevails in summer by 5.8%, while there is modest cloud suppression in winter nights. Statistically linking the cloud patterns with city properties, geographic locations, and climate backgrounds, we found that larger city size and stronger surface heating are primarily responsible for summer local cloud enhancement diurnally. Moisture and energy background control the urban cloud cover anomalies seasonally. Under strong mesoscale circulations induced by terrains and land–water contrasts, urban clouds exhibit considerable nighttime enhancement during warm seasons, which is relevant to strong urban surface heating interacting with these circulations, but other local and climate impacts remain complicated and inconclusive. Our research unveils extensive urban influences on local cloud patterns, but the effects are diverse depending on time, location, and city properties. The comprehensive observational study on urban–cloud interactions calls for more in-depth research on urban cloud life cycles and their radiative and hydrologic implications under the urban warming context.
Mechanistic roles of metal- and ligand-protonated species in hydrogen evolution with [Cp*Rh] complexes
Authors: Henke Wade C. , Peng Yun , Meier Alex A. , Fujita Etsuko , Grills David C. , Polyansky Dmitry E. , Blakemore James D.
Published: May 2023

Protonation reactions involving organometallic complexes are ubiquitous in redox chemistry and often result in the generation of reactive metal hydrides. However, some organometallic species supported by η
5
-pentamethylcyclopentadienyl (Cp*) ligands have recently been shown to undergo ligand-centered protonation by direct proton transfer from acids or tautomerization of metal hydrides, resulting in the generation of complexes bearing the uncommon η
4
-pentamethylcyclopentadiene (Cp*H) ligand. Here, time-resolved pulse radiolysis (PR) and stopped-flow spectroscopic studies have been applied to examine the kinetics and atomistic details involved in the elementary electron- and proton-transfer steps leading to complexes ligated by Cp*H, using Cp*Rh(bpy) as a molecular model (where bpy is 2,2′-bipyridyl). Stopped-flow measurements coupled with infrared and UV-visible detection reveal that the sole product of initial protonation of Cp*Rh(bpy) is [Cp*Rh(H)(bpy)]
+
, an elusive hydride complex that has been spectroscopically and kinetically characterized here. Tautomerization of the hydride leads to the clean formation of [(Cp*H)Rh(bpy)]
+
. Variable-temperature and isotopic labeling experiments further confirm this assignment, providing experimental activation parameters and mechanistic insight into metal-mediated hydride-to-proton tautomerism. Spectroscopic monitoring of the second proton transfer event reveals that both the hydride and related Cp*H complex can be involved in further reactivity, showing that [(Cp*H)Rh] is not necessarily an off-cycle intermediate, but, instead, depending on the strength of the acid used to drive catalysis, an active participant in hydrogen evolution. Identification of the mechanistic roles of the protonated intermediates in the catalysis studied here could inform design of optimized catalytic systems supported by noninnocent cyclopentadienyl-type ligands.
Architecture and genomic arrangement of the MurE–MurF bacterial cell wall biosynthesis complex
Authors: Shirakawa Karina T. , Sala Fernanda Angélica , Miyachiro Mayara M. , Job Viviana , Trindade Daniel Maragno , Dessen Andréa
Published: May 2023

Peptidoglycan (PG) is a central component of the bacterial cell wall, and the disruption of its biosynthetic pathway has been a successful antibacterial strategy for decades. PG biosynthesis is initiated in the cytoplasm through sequential reactions catalyzed by Mur enzymes that have been suggested to associate into a multimembered complex. This idea is supported by the observation that in many eubacteria,
mur
genes are present in a single operon within the well conserved
dcw
cluster, and in some cases, pairs of
mur
genes are fused to encode a single, chimeric polypeptide. We performed a vast genomic analysis using >140 bacterial genomes and mapped Mur chimeras in numerous phyla, with Proteobacteria carrying the highest number. MurE–MurF, the most prevalent chimera, exists in forms that are either directly associated or separated by a linker. The crystal structure of the MurE–MurF chimera from
Bordetella pertussis
reveals a head-to-tail, elongated architecture supported by an interconnecting hydrophobic patch that stabilizes the positions of the two proteins. Fluorescence polarization assays reveal that MurE–MurF interacts with other Mur ligases via its central domains with K
D
s in the high nanomolar range, backing the existence of a Mur complex in the cytoplasm. These data support the idea of stronger evolutionary constraints on gene order when encoded proteins are intended for association, establish a link between Mur ligase interaction, complex assembly and genome evolution, and shed light on regulatory mechanisms of protein expression and stability in pathways of critical importance for bacterial survival.
Entropic control of the free-energy landscape of an archetypal biomolecular machine
Authors: Ray Korak Kumar , Kinz-Thompson Colin D. , Fei Jingyi , Wang Bin , Lin Qiao , Gonzalez Ruben L.
Published: May 2023

Biomolecular machines are complex macromolecular assemblies that utilize thermal and chemical energy to perform essential, multistep, cellular processes. Despite possessing different architectures and functions, an essential feature of the mechanisms of action of all such machines is that they require dynamic rearrangements of structural components. Surprisingly, biomolecular machines generally possess only a limited set of such motions, suggesting that these dynamics must be repurposed to drive different mechanistic steps. Although ligands that interact with these machines are known to drive such repurposing, the physical and structural mechanisms through which ligands achieve this remain unknown. Using temperature-dependent, single-molecule measurements analyzed with a time-resolution-enhancing algorithm, here, we dissect the free-energy landscape of an archetypal biomolecular machine, the bacterial ribosome, to reveal how its dynamics are repurposed to drive distinct steps during ribosome-catalyzed protein synthesis. Specifically, we show that the free-energy landscape of the ribosome encompasses a network of allosterically coupled structural elements that coordinates the motions of these elements. Moreover, we reveal that ribosomal ligands which participate in disparate steps of the protein synthesis pathway repurpose this network by differentially modulating the structural flexibility of the ribosomal complex (i.e., the entropic component of the free-energy landscape). We propose that such ligand-dependent entropic control of free-energy landscapes has evolved as a general strategy through which ligands may regulate the functions of all biomolecular machines. Such entropic control is therefore an important driver in the evolution of naturally occurring biomolecular machines and a critical consideration for the design of synthetic molecular machines.
Paleolakes and socioecological implications of last glacial “greening” of the South African interior
Authors: Carr Andrew S. , Chase Brian M. , Birkinshaw Stephen J. , Holmes Peter J. , Rabumbulu Mulalo , Stewart Brian A.
Published: May 2023

Determining the timing and drivers of Pleistocene hydrological change in the interior of South Africa is critical for testing hypotheses regarding the presence, dynamics, and resilience of human populations. Combining geological data and physically based distributed hydrological modeling, we demonstrate the presence of large paleolakes in South Africa’s central interior during the last glacial period, and infer a regional-scale invigoration of hydrological networks, particularly during marine isotope stages 3 and 2, most notably 55 to 39 ka and 34 to 31 ka. The resulting hydrological reconstructions further permit investigation of regional floral and fauna responses using a modern analog approach. These suggest that the climate change required to sustain these water bodies would have replaced xeric shrubland with more productive, eutrophic grassland or higher grass-cover vegetation, capable of supporting a substantial increase in ungulate diversity and biomass. The existence of such resource-rich landscapes for protracted phases within the last glacial period likely exerted a recurrent draw on human societies, evidenced by extensive pan-side artifact assemblages. Thus, rather than representing a perennially uninhabited hinterland, the central interior’s underrepresentation in late Pleistocene archeological narratives likely reflects taphonomic biases stemming from a dearth of rockshelters and regional geomorphic controls. These findings suggest that South Africa’s central interior experienced greater climatic, ecological, and cultural dynamism than previously appreciated and potential to host human populations whose archaeological signatures deserve systematic investigation.
Quantifying the partial ionization effect of gold in the transition region between condensed matter and warm dense matter
Authors: Li Zhiguo , Wang Xiang , Hou Yong , Yu Yuying , Li Guojun , Hao Long , Li Xuhai , Geng Huayun , Dai Chengda , Wu Qiang , Mao Ho-Kwang , Hu Jianbo
Published: May 2023

It is now well known that solids under ultra-high-pressure shock compression will enter the warm dense matter (WDM) regime which connects condensed matter and hot plasma. How condensed matter turns into the WDM, however, remains largely unexplored due to the lack of data in the transition pressure range. In this letter, by employing the unique high-Z three-stage gas gun launcher technique developed recently, we compress gold into TPa shock pressure to fill the gap inaccessible by the two-stage gas gun and laser shock experiments. With the aid of high-precision Hugoniot data obtained experimentally, we observe a clear softening behavior beyond ~560 GPa. The state-of-the-art ab-initio molecular dynamics calculations reveal that the softening is caused by the ionization of 5d electrons in gold. This work quantifies the partial ionization effect of electrons under extreme conditions, which is critical to model the transition region between condensed matter and WDM.
Mechanistic insights into the regulation of cell wall hydrolysis by FtsEX and EnvC at the bacterial division site
Authors: Xu Xin , Li Jianwei , Chua Wan-Zhen , Pages Martin A. , Shi Jian , Hermoso Juan A. , Bernhardt Thomas , Sham Lok-To , Luo Min
Published: May 2023

The peptidoglycan (PG) cell wall produced by the bacterial division machinery is initially shared between the daughters and must be split to promote cell separation and complete division. In gram-negative bacteria, enzymes that cleave PG called amidases play major roles in the separation process. To prevent spurious cell wall cleavage that can lead to cell lysis, amidases like AmiB are autoinhibited by a regulatory helix. Autoinhibition is relieved at the division site by the activator EnvC, which is in turn regulated by the ATP-binding cassette (ABC) transporter-like complex called FtsEX. EnvC is also known to be autoinhibited by a regulatory helix (RH), but how its activity is modulated by FtsEX and the mechanism by which it activates the amidases have remained unclear. Here, we investigated this regulation by determining the structure ofPseudomonas aeruginosaFtsEX alone with or without bound ATP, in complex with EnvC, and in a FtsEX–EnvC–AmiB supercomplex. In combination with biochemical studies, the structures reveal that ATP binding is likely to activate FtsEX-EnvC and promote its association with AmiB. Furthermore, the AmiB activation mechanism is shown to involve a RH rearrangement. In the activated state of the complex, the inhibitory helix of EnvC is released, freeing it to associate with the RH of AmiB, which liberates its active site for PG cleavage. These regulatory helices are found in many EnvC proteins and amidases throughout gram-negative bacteria, suggesting that the activation mechanism is broadly conserved and a potential target for lysis-inducing antibiotics that misregulate the complex.
Contraception ends the genetic maintenance of human same-sex sexual behavior
Authors: Song Siliang , Zhang Jianzhi
Published: May 2023

Because human same-sex sexual behavior (SSB) is heritable and leads to fewer offspring, it is puzzling why SSB-associated alleles have not been selectively purged. Current evidence supports the antagonistic pleiotropy hypothesis that SSB-associated alleles benefit individuals exclusively performing opposite-sex sexual behavior by increasing their number of sexual partners and consequently their number of offspring. However, by analyzing the UK Biobank, here, we show that having more sexual partners no longer predicts more offspring since the availability of oral contraceptives in the 1960s and that SSB is now genetically negatively correlated with the number of offspring, suggesting a loss of SSB’s genetic maintenance in modern societies.
Microstructure and solidification behaviour of CuNiSiAl eutectic multi-principal element alloy
Authors: An Xulong , Zhang Xiaotong , Sui Yudong , Hu Jing , Xu Zhengxiang , Wei Wei , Chu Chenglin , Sun Wenwen
Published: May 2023

Eutectic multi-principal element alloys show great promise due to their exceptional castability, unique near-equilibrium microstructure, and controllability. In this study, a novel copper-containing Cu42.3Ni30Si15Al12.7 eutectic multi-principal element alloy was designed and investigated. The microstructure of the alloy is composed of primary phase Ni2Si and eutectic phase (FCC(Cu) + BCC(NiAl)). The eutectic reaction temperature is 1004°C. Understanding the solidification process is crucial for optimising solidification parameters and subsequent annealing. The as-cast Cu42.3Ni30Si15Al12.7 alloy exhibits high micro-hardness (400 ± 2.4 HV) and compressive fracture strength (1511 MPa)
Magnetic-Field-Induced Sign Changes of Thermal Expansion in DyCrO4
Authors: He Jin-Cheng , Pan Zhao , Su Dan , Shen Xu-Dong , Zhang Jie , Lu Da-Biao , Zhao Hao-Ting , Cong Jun-Zhuang , Liu En-Ke , Long You-Wen , Sun Young
Published: May 2023

The anharmonicity of lattice vibration is mainly responsible for the coefficient of thermal expansion (CTE) of materials. External stimuli, such as magnetic and electric fields, thus cannot effectively change the CTE, much less the sign variation from positive to negative or vice versa. In this study, we report significant magnetic field effects on the CTE of zircon- and scheelite-type DyCrO4 prepared at ambient and high pressures, respectively. At zero field, the zircon-type DyCrO4 exhibits a negative CTE below the ferromagnetic-order temperature of 23 K. With increasing field up to ≥1.0 T, however, the sign of the CTE changes from negative to positive. In the scheelite phase, magnetic field can change the initially positive CTE to be negative with a field up to 2.0 T, and then a reentrant positive CTE is induced by enhanced fields ≥3.5 T. Both zircon and scheelite phases exhibit considerable magnetostrictive effects with the absolute values as high as ∼ 800 ppm at 2 K and 10 T. The strong spin–lattice coupling is discussed to understand the unprecedented sign changes of the CTE caused by applying magnetic fields. The current DyCrO4 provides the first example of field-induced sign change of thermal expansion, opening up a way to readily control the thermal expansion beyond the conventional chemical substitution.
Possible Room-Temperature Ferromagnetic Semiconductors
Authors: You Jing-Yang , Dong Xue-Juan , Gu Bo , Su Gang
Published: May 2023

Magnetic semiconductors integrate the dual characteristics of magnets and semiconductors. It is difficult to manufacture magnetic semiconductors that function at room temperature. Here, we review a series of our recent theoretical predictions on room-temperature ferromagnetic semiconductors. Since the creation of two-dimensional (2D) magnetic semiconductors in 2017, there have been numerous developments in both experimental and theoretical investigations. By density functional theory calculations and model analysis, we recently predicted several 2D room-temperature magnetic semiconductors, including CrGeSe3 with strain, CrGeTe3/PtSe2 heterostructure, and technetium-based semiconductors (TcSiTe3, TcGeSe3, and TcGeTe3), as well as PdBr3 and PtBr3 with a potential room-temperature quantum anomalous Hall effect. Our findings demonstrated that the Curie temperature of these 2D ferromagnetic semiconductors can be dramatically enhanced by some external fields, such as strain, construction of heterostructure, and electric field. In addition, we proposed appropriate doping conditions for diluted magnetic semiconductors, and predicted the Cr doped GaSb and InSb as possible room-temperature magnetic semiconductors.
The activated scaling behavior of quantum Griffiths singularity in two-dimensional superconductors
Authors: Cui Zihan , Pan Longxin , Fang Jingchao , Qi Shichao , Xing Ying , Liu Haiwen , Liu Yi , Wang Jian
Published: May 2023

Quantum Griffiths singularity (QGS) is characterized by the divergence of the dynamical critical exponent with the activated scaling law and has been widely observed in various two-dimensional superconductors. Recently, the direct activated scaling analysis with the irrelevant correction was proposed and successfully used to analyze the experimental data of crystalline PdTe2 and polycrystalline

β

-W films, which provides new evidence of QGS. Here we show that the direct activated scaling analysis is applicable to the experimental data in different superconducting films, including tri-layer Ga films and LaAlO3/SrTiO3 interface superconductors. When taking the irrelevant correction into account, we calculate the corrected sheet resistance at ultralow temperatures. The scaling behavior of the corrected resistance in a comparably large temperature regime and the theoretical fitting of the phase boundary give unambiguous evidence of QGS. Compared to previous methods based on finite size scaling, the direct activated scaling analysis represents a more direct and precise way to analyze the experimental data of QGS in diverse two-dimensional superconductors.
Observation of high phase velocity of dust acoustic waves with elongated dust grains in a cryogenic dusty plasma experiment
Authors: Chai Kil-Byoung
Published: May 2023

Self-excited dust acoustic waves (DAWs) with a high phase velocity were observed in the cryogenic dusty plasma experiment, where submillimeter, elongated, and fractal-like water-ice dust grains are formed. The phase velocity of the observed DAWs was obtained by the fast Fourier transform of the sequential images of the DAWs and it ranges from 8 to 15 cm s−1. The length of the dust grains was measured between 100 and 250 μm and the thermal speed of the dust grains was obtained between 1.5 and 2.8 cm s−1. It is shown that the linear theory including the effect of the dust thermal speed can explain the observed fast phase velocity. The possible mechanisms by which the submillimeter dust grains gain such high kinetic energies are discussed.
An ab initio study of the electronic properties of helium in wurtzite gallium nitride
Authors: Alfieri Giovanni , Fujii Yusuke , Micheletto Ruggero
Published: May 2023

Impurities and their complexes with intrinsic point defects, e.g. vacancies, can alter the opto-electronic properties of semiconductors. Among such impurities, helium is incorporated into gallium nitride (GaN) by ion implantation, for wafer splitting and for device isolation purposes. Yet, despite the technological importance of such impurity, it is not known whether or not He is electrically active in GaN or what its impact on n- or p-type dopants is. For this reason, we carried out a density functional theory study of substitutional He and related complexes (vacancies and dopants) in wurtzite GaN. We employed the generalized gradient approximation and overcame the band gap energy underestimation, by a posteriori corrections. It is found that He is unstable at N-sites, moving to interstitial sites and forming a N vacancy (V

N
). This was observed for the case of substitutional He and for He complexed with n- or p-type dopants. The formation of V

N
, in such defects, gives rise to donor states close to the valence band edge (E
V
). On the other hand, the presence of a gallium vacancy (V

G
a

) leads to the formation of an energetically stable complex that gives rise to acceptor states close to the conduction band edge (E
C
). Our findings are then discussed in the light of previous experimental reports on GaN device isolation.
On the rate of convergence of an exponential scheme for the non-linear stochastic Schrödinger equation with finite-dimensional state space
Authors: Mora Carlos M , Muñoz Mario
Published: May 2023

We address the numerical solution of the finite-dimensional non-linear stochastic Schrödinger equation, which is a locally Lipschitz stochastic differential equation modeling, for instance, quantum measurement processes. We study the rate of weak convergence of an exponential scheme that reproduces the norm of the desired solution by projecting onto the unit sphere. This justifies the use of the Talay-Tubaro extrapolation procedure in the numerical simulation of open quantum systems. In particular, we prove that an Euler-Exponential scheme converges with weak-order one, and we obtain the leading order term of its weak error expansion with respect to the step-size. Then, applying the Talay-Tubaro extrapolation procedure to the Euler-Exponential scheme under consideration we get a second-order method for computing the mean values of smooth functions of the solution of the non-linear stochastic Schrödinger equation. We also prove that the exponential scheme under study has order of strong convergence 1/2, which gives theoretical support to the use of the multilevel Monte Carlo method in simulating open quantum systems. We present a numerical experiment with a quantized electromagnetic field in interaction with a reservoir that illustrates the good performance of the weak second-order method, and the multilevel Monte Carlo method.
Structure, stability and defect energetics of interfaces formed between conventional and transformed phases in Cu–Nb layered nanocomposite
Authors: Saikia Ujjal , Sahariah Munima B , Dutta Biswanath , Pandey Ravindra
Published: May 2023

Layered nanocomposite material having fcc-bcc interface with Kurdjumov-Sachs interface orientation relation has shown great potential as radiation resistant structural material for future fusion energy reactors. The superior radiation resistant properties of this material are attributed to it’s special fcc-bcc interface structure. In this study we have reported a stable interface between conventional bcc phase of Nb and transformed bcc phase of Cu. This bcc-bcc interface is found to be stable from both strain-energy and dynamical stability analysis. We have also shown that the bcc-bcc interface has different defect energetics behaviour compared to previously reported fcc-bcc interface which has a negative impact on the self annihilation property of the material against radiation induced defects. These aspects should be carefully considered in the future design of robust layered material for extreme radiation environment.
Influence of coulomb damping on wave propagation behaviors of nonlinear nonconservative phononic chains/lattices
Authors: Sepehri Soroush , Bodaghi Mahdi
Published: May 2023

Fascinating nonlinearity-induced behavior of phononic crystals (PCs) has recently become a hot research topic in the community. However, due to the limitations in the analytical modelling of damping in dynamic systems, the study of damped PCs has not received proper attention. In this paper, the influence of Coulomb damping on the wave propagation behavior of cubically nonlinear monoatomic phononic chains is investigated. To do so, the nonlinear dispersion relation is obtained analytically using the well-established multiple scales method and the band structure of the damped nonlinear chains is compared to the ones corresponding to the linear and nonlinear undamped chains. Due to the coupling between the amplitude and the frequency, stemmed from the nonlinear nature of the chain, Coulomb damping can lead to lower dispersion frequencies in the chain. The formulation and results are then expanded to 2D nonlinear lattices. The present manuscript is the first attempt to capture the effect of Coulomb damping on the wave propagation behavior of nonlinear lattices and the results put us one step closer to developing a comprehensive analytical model for the behavior of damped PCs which can in turn lead to invaluable design concepts for nonlinear nonconservative wave-manipulation devices.
Defect solitons supported by optical lattice with saturable nonlinearity in fractional Schrödinger equation
Authors: Wang Shengyao , Xia Tuanjie , Chen Weijun , Zhao Peng
Published: May 2023

We address the existence, stability, and propagation dynamics of both one- and two-dimensional defect solitons supported by optical lattice with saturable nonlinearity in fractional Schrödinger equation. Under the influence of fractional effect, in one dimension, solitons exist stably in limited regions in the semi-infinite bandgap with high and low power both for a negative and positive defect lattice. In the first bandgap, solitons are stable for negative defect lattice, while unstable for positive defect lattice. In the second bandgap, only stable solitons can propagate in small regions for the positive defect lattice. With increasing the Lévy index from 1 to 2, the power of the defect solitons decreases in the semi-infinite bandgap and increases in the first bandgap. Linear stability analyses show that, the domains of stability for defect solitons strongly depend on the Lévy index, defect strength and different bandgaps. In two dimension, defect solitons can exist stably at high and moderate power regions in the semi-infinite bandgap and all regions in the first bandgap with negative defect lattice, while they are stable at high, moderate and low power regions in the semi-infinite bandgap and unstable in the first bandgap with positive defect lattice.
Small polaron hopping transport mechanism, dielectric relaxation and electrical conduction in NiAl2O4 electro-ceramic spinel oxide
Authors: Iqbal Yousaf , Shah Waqar Hussain , Khan Bisma , Javed Muhammad , Ullah Hayat , Khan Nadia , Khan Abdul Rauf , Asghar Ghulam , Safeen Akif
Published: May 2023

In this study, the frequency and temperature dependent dielectric relaxation and electrical conduction mechanisms in NiAl2O4 spinel oxide ceramic have been explored in a frequency range of

50
−
10
×

10

6

Hz

over a measured temperature from 163–283 K. The polycrystalline NiAl2O4 was synthesized via solid state reaction route and sintered at 1000 °C. The room temperature x-ray powder diffraction pattern confirmed the formation of NiAl2O4 spinel phase with Fd3m space group. The surface morphology of the sample was investigated by scanning electron microscopy and chemical properties by Fourier transform infrared spectroscopic analysis. Complex impedance studies revealed the presence of relaxation time distribution and charge carriers were found to be thermally activated. The Nyquist plots exhibited depressed semicircles and their fitting by an equivalent circuit model with configuration (RGCG)(RGBCGB) resolved the contributions of grains and grain-boundaries to the electrical transport properties of the material. Electrical conductivity analysis followed the Jonscher’s power law behavior and the frequency exponent suggested small polaron hopping as the governing transport mechanism in NiAl2O4 spinel oxide. Non-Debye type nature of dielectric relaxation was confirmed by the complex modulus analysis whereas dielectric constant and tangent loss analysis verified that the hopping mechanism was thermally activated.
Why cosmic voids matter: nonlinear structure & linear dynamics
Authors: Schuster Nico , Hamaus Nico , Dolag Klaus , Weller Jochen
Published: May 2023

We use the Magneticum suite of state-of-the-art hydrodynamical simulations to identify
cosmic voids based on the watershed technique and investigate their most fundamental properties
across different resolutions in mass and scale. This encompasses the distributions of void sizes,
shapes, and content, as well as their radial density and velocity profiles traced by the
distribution of cold dark matter particles and halos. We also study the impact of various tracer
properties, such as their sparsity and mass, and the influence of void merging on these summary
statistics. Our results reveal that all of the analyzed void properties are physically related to
each other and describe universal characteristics that are largely independent of tracer type and
resolution. Most notably, we find that the motion of tracers around void centers is perfectly
consistent with linear dynamics, both for individual, as well as stacked voids. Despite the large
range of scales accessible in our simulations, we are unable to identify the occurrence of
nonlinear dynamics even inside voids of only a few Mpc in size. This suggests voids to be among
the most pristine probes of cosmology down to scales that are commonly referred to as highly
nonlinear in the field of large-scale structure.
Constraints on the phase transition of early dark energy with the CMB anisotropies
Authors: Hayashi Shintaro , Minoda Teppei , Ichiki Kiyotomo
Published: May 2023

Early dark energy (EDE) models have attracted attention in the context of the recent problem of the Hubble tension. Here we extend these models by taking into account the new density fluctuations generated by the EDE which decays around the recombination phase.
We solve the evolution of the density perturbations in dark energy fluid generated at the phase transition of EDE as isocurvature perturbations. Assuming that the isocurvature mode is characterized by a power-law power spectrum and is uncorrelated with the standard adiabatic mode, we calculate the CMB angular power spectra. By comparing them to the Planck data using the Markov-Chain Monte Carlo method, we obtained zero-consistent values of the EDE parameters and H
0 = 67.56+0.65
-0.66 km s-1 Mpc-1 at 68 % CL. This H
0 value is almost the same as the Planck value in the ΛCDM model, H
0 = 67.36 ± 0.54 km s-1 Mpc-1, and there is still a ∼ 3.5σ tension between the CMB and Type Ia supernovae observations. Including CMB lensing, BAO, supernovae and SH0ES data sets, we find H
0 = 68.94+0.47
-0.57 km s-1 Mpc-1 at 68 % CL. The amplitude of the fluctuations induced by the phase transition of the EDE is constrained to be less than 1–2 percent of the amplitude of the adiabatic mode. This is so small that such non-standard fluctuations cannot appear in the CMB angular spectra.
In conclusion, the isocurvature fluctuations induced by our simplest EDE phase transition model do not explain the Hubble tension well.
Halo occupation distribution of Emission Line Galaxies: fitting method with Gaussian processes
Authors: Rocher Antoine , Ruhlmann-Kleider Vanina , Burtin Etienne , de Mattia Arnaud
Published: May 2023

The halo occupation distribution (HOD) framework is an empirical method to describe the
connection between dark matter halos and galaxies, which is constrained by small scale clustering
data. Efficient fitting procedures are required to scan the HOD parameter space. This paper
describes such a method based on Gaussian Processes to iteratively build a surrogate model of the
posterior of the likelihood surface from a reasonable amount of likelihood computations, typically
two orders of magnitude less than standard Monte Carlo Markov chain algorithms. Errors in the
likelihood computation due to stochastic HOD modelling are also accounted for in the method we
propose. We report results of reproducibility, accuracy and stability tests of the method derived
from simulation, taking as a test case star-forming emission line galaxies, which constitute the
main tracer of the Dark Energy Spectroscopic Instrument and have so far a poorly constrained
galaxy-halo connection from observational data.
What geometrically constrained models can tell us about real-world protein contact maps
Authors: Jasmin Güven J , Molkenthin Nora , Mühle Steffen , Mey Antonia S J S
Published: May 2023

The mechanisms by which a protein’s 3D structure can be determined based on its amino acid sequence have long been one of the key mysteries of biophysics. Often simplistic models, such as those derived from geometric constraints, capture bulk real-world 3D protein-protein properties well. One approach is using protein contact maps (PCMs) to better understand proteins’ properties. In this study, we explore the emergent behaviour of contact maps for different geometrically constrained models and compare them to real-world protein systems. Specifically, we derive an analytical approximation for the distribution of amino acid distances, denoted as P(s), using a mean-field approach based on a geometric constraint model. This approximation is then validated for amino acid distance distributions generated from a 2D and 3D version of the geometrically constrained random interaction model. For real protein data, we show how the analytical approximation can be used to fit amino acid distance distributions of protein chain lengths of L ≈ 100, L ≈ 200, and L ≈ 300 generated from two different methods of evaluating a PCM, a simple cutoff based method and a shadow map based method. We present evidence that geometric constraints are sufficient to model the amino acid distance distributions of protein chains in bulk and amino acid sequences only play a secondary role, regardless of the definition of the PCM.