bluuebunny/crossref_metadata_2025 huggingface dataset:
Functionalized Magnetic Nanoparticles in Sample Pre-treatment
Authors: Simon Sanu Mathew , Sajna M. S. , Prakashan V. P. , Jose Twinkle Anna , Biju P. R. , Joseph Cyriac , Unnikrishnan N. V.
Published: July 2021

The low amount of analyte and inevitable intervention of complicated matrices during instrumental analysis present an ongoing challenge for analysts in tracking proficient analysis in complex samples. Hence, suitable sample pretreatment is essential in investigations, which aim to clean up, separate and concentrate analytes of concern. It has been of great interest to develop magnetic-based adsorbent materials for the separation of materials and they can be applied in an extensive range of fields like magnetic fluids, catalysis, magnetic resonance imaging and environmental remediation since the adsorbent material does not need to be packed into any type of device. The inherent characteristics of magnetic nanoparticles along with their excellent performance have resulted in functionalized magnetic nanoparticles being very attractive in various sample preparation methods compared with other conventional sample-preparation sorbents. The benefits of magnetic nanoparticles include high sensitivity and rapid extraction which arises due to the high surface-area-to-volume ratio. Moreover, magnetic nanoparticles shorten the separation process and increase the pace of separation, enabling the extraction method to be finished a few seconds or even minutes faster. This chapter mainly describes the application of functionalized magnetic nanoparticles in the separation and analysis of analyte pre-concentration from a mixture of matrices.
The distribution of high-quality internal standard lines and their selection method based on the Q-value in portable laser-induced breakdown spectroscopy
Authors: Yan Jiujiang , Shi Yating , Liu Ke , Li Hongjun , Tang Zhiyang , Chen Wei , Jiang Wei , Li Qiaomin , Tang Yun , Li Xiangyou
Published: July 2021

The execution process of the line selection method (Q-value method) based on Q value in portable LIBS.
Combined photothermal-immunotherapy via poly-tannic acid coated PLGA nanoparticles for cancer treatment
Authors: Huang Xingyue , Tian Xuehao , Zhang Qing , Hu Haiyan , Gao Jiahui , Ma Baonan , Wu Kai , Bai Jie , Du Shouying , Lu Yang , Han Ning
Published: July 2021

Photothermal therapy (PTT) is able to ablate tumors via hyperthermia, while immunotherapy could prevent tumor recurrence and metastasis by activating the host immune responses.
Poly-ion complex micelles effectively deliver CoA-conjugated CPT1A inhibitors to modulate lipid metabolism in brain cells
Authors: Paraiso West Kristian D. , Garcia-Chica Jesús , Ariza Xavier , Zagmutt Sebastián , Fukushima Shigeto , Garcia Jordi , Mochida Yuki , Serra Dolors , Herrero Laura , Kinoh Hiroaki , Casals Núria , Kataoka Kazunori , Rodríguez-Rodríguez Rosalía , Quader Sabina
Published: July 2021

C75-CoA is a capable inhibitor of fatty acid oxidation but is anionic and has low cellular permeability. We prepared charge-neutralizing poly-ion complex micelles to efficiently deliver the drug into glioma cells and neurons in 2D and 3D cultures.
Structure, isomerization and dimerization processes of naringenin flavonoids
Authors: González Moreno Ana , Prieto Pilar , Ruiz Delgado M. Carmen , Domínguez Eva , Heredia Antonio , de Cózar Abel
Published: July 2021

In this study, theoretical and experimental results on molecular structure of the plant flavonoids naringenin chalcone and naringenin, analysis of the cyclization–isomerization reaction and the formation of homo- and heterodimers are reported.
Theoretical study of the dissociative photodetachment dynamics of the hydrated superoxide anion cluster
Authors: Hashimoto Yu , Saito Kohei , Takayanagi Toshiyuki , Tachikawa Hiroto
Published: July 2021

Theoretical calculations that can account for nuclear quantum effects were carried out to interpret the experimentally-measured photoelectron spectra of the O2−·H2O anion complex.
Tunable valley polarization in Janus WSSe by magnetic proximity coupling to a CrI3 layer
Authors: She X. C. , Zhang R. L. , Zhao Jin-Zhu , Qi D. X. , Zou Y. , Peng Ru-Wen
Published: July 2021

The direction of VP can be flipped by manipulating the layer alignment without reversing the magnetization direction of the substrate. We suggest that the hybridization between the bands of WSSe and the substrate plays an important role.
Oxygen adsorption on high-index faceted Pt nanoparticles
Authors: Lin Wu-Yang , Huang Rao , Li Lei , Wen Yu-Hua
Published: July 2021

The oxygen adsorption behaviors of three 24-facet nanoparticles respectively enclosed by {310}, {311}, and {331} high-index facets are investigated.
Identity of the local and macroscopic dynamic elastic responses in supercooled 1-propanol
Authors: Weigl Peter , Hecksher Tina , Dyre Jeppe C. , Walther Thomas , Blochowicz Thomas
Published: July 2021

As a surprising, non-trivial result of comparing the local elastic properties with those from macroscopic shear measurements, it was found that the responses are identical, even in their time dependence.
Intercalation/deintercalation of solvated Mg2+ into/from graphite interlayers
Authors: Shimizu Masahiro , Nakahigashi Atsuhito , Arai Susumu
Published: July 2021

We reconsider the potential of graphite as a negative electrode material for Mg-ion batteries. The formation of a ternary graphite intercalation compound (GIC) with a stage structure resulted in a reversible capacity of approximately 200 mA h g−1.
Synergistic recycling and conversion of spent Li-ion battery leachate into highly efficient oxygen evolution catalysts
Authors: Chen Zhijie , Zou Wensong , Zheng Renji , Wei Wenfei , Wei Wei , Ni Bing-Jie , Chen Hong
Published: July 2021

A one-pot synergetic recycling and regeneration strategy to develop highly efficient tri-metal OER electrocatalysts from spent LIB leachates is demonstrated.
Interfacing sugar-based surfactant micelles and Cu nanoparticles: a nanoreactor for C–S coupling reactions in water
Authors: Ge Xin , Song Weili , He Xi , Yang Jinguo , Qian Chao , Zhou Shaodong , Liu Xuemin
Published: July 2021

A simple and sustainable synergistic catalytic protocol by interfacing sugar-based surfactant nanomicelles and Cu2O nanoparticles is developed for C–S coupling reactions in water.
Evaluation of nanodebris produced byin vitrodegradation of titanium-based dental implants in the presence of bacteria using single particle and single cell inductively coupled plasma mass spectrometry
Authors: Cosmi Marzia , Gonzalez-Quiñonez Nathaly , Tejerina Díaz Pablo , Manteca Ángel , Blanco-González Elisa , Bettmer Jörg , Montes-Bayón María , Corte-Rodriguez Mario
Published: July 2021

Titanium oxide nanoparticles released by titanium implants can be detected and characterized by single-particle ICP-MS and transmission electron microscopy.
A perspective on the evolving role of stable isotope analysis and the emergence of cavity enhanced spectroscopy as a potent tool
Authors: Maithani Sanchi , Maity Abhijit , Pradhan Manik
Published: July 2021

Applications of isotope analysis and the role of cavity enhanced absorption spectroscopy as an emerging tool.
Study of matrix effects in laser-induced breakdown spectroscopy by laser defocus and temporal resolution
Authors: Wang Wei , Sun Lanxiang , Zhang Peng , Chen Tong , Zheng Liming , Qi Lifeng
Published: July 2021

Taking the spectrum generated by the pure sample as the matrix background and subtracting the intensity value of the matrix background at the analysis line can reduce the interference of the matrix effects.
Effect of molecular chirality on the collagen self-assembly
Authors: Zhu Weizhe , Li Ke , Liu Qi , Zhong Huaying , Xu Chengzhi , Zhang Juntao , Kou Huizhi , Wei Benmei , Wang Haibo
Published: July 2021

The function of molecular chirality in collagen self-assembly was presented.
A facile sol–gel method based on urea–SnCl2 deep eutectic solvents for the synthesis of SnO2/SiO2 with high oxidation desulfurization activity
Authors: Liu Xiao-yi , Li Xiu-ping , Zhao Rong-xiang , Zhang Hao
Published: July 2021

The n%-SnO2/SiO2 (n = 2, 4, 6) supported catalyst was prepared by the sol–gel and calcination method. Compared with the traditional impregnation method, the catalyst prepared by sol–gel method has higher oxidative desulfurization activity.
Dissection of the potential pharmacological mechanism ofRhizoma coptidiswater extract against inflammation in diabetes mellitusviachemical profiling, network pharmacology and experimental validation
Authors: Zhang Feng-xiang , Li Min , Yuan Yu-lin-lan , Cui Shuang-Shuang , Qiu Zuo-cheng , Li Rui-man
Published: July 2021

Elucidating the therapeutical basis and functional mechanism of traditional Chinese medicine (TCM) is still a challenge faced by researchers since the effects of TCM are always achieved by the interactions of multiple components and multiple targets.
In-depth study on the structures and properties of rare-earth-containing perovskite materials
Authors: Zhang Hongtu , Zeng Zhichao , Shi Xiaomeng , Du Yaping
Published: July 2021

The structure, morphology, composition and performance characterization techniques of rare-earth-containing perovskites were reviewed, providing in-depth and systematical research strategies.
Partial sulfur vacancies created by carbon–nitrogen deposition of MoS2 for high-performance overall electrocatalytic water splitting
Authors: Chen Wenxia , Wei Wei , Wang Kefeng , Cui Jinhai , Zhu Xingwang , Ostrikov Kostya (Ken)
Published: July 2021

The bifunctional electrocatalyst C–N-MoS2/CC-700 with Mo–N links and unsaturated S defects is designed by bi-elemental C and N doping in the CVD process.
Biomimetic microcavity interfaces for a label-free capture of pathogens in the fluid bloodstream by vortical crossflow filtration
Authors: Zheng Liyuan , Zheng Xiaobo , Yuan Shanshan , Xu Weide , Zhang Changhuan , Zhang Xingding , Fan Zhiyuan , Wang Jilong , Wang Zheng , Huang Jinhai , Deng Junjie
Published: July 2021

Our study constructs a novel gill-raker like interface for label-free transport and deposit pathogens rapidly into microcavity instead of introducing active agents to binding bacteria.
Enhancement of photoluminescence and the stability of CsPbX3(X = Cl, Br, and I) perovskite nanocrystals with phthalimide passivation
Authors: Dutt V. G. Vasavi , Akhil Syed , Mishra Nimai
Published: July 2021

Dramatic improvement of photoluminescence quantum yield (PLQY) and the stability of phthalimide passivated CsPbCl3, CsPbBr3, and CsPbI3 NCs under ambient light and UV light.
Simultaneous detection of multiple proteases using a non-array nanopore platform
Authors: Chen Xiaohan , Zhang Youwen , Guan Xiyun
Published: July 2021

By monitoring protease degradation of a single peptide substrate containing two cleavage sites in a single nanopore, simultaneous detection and quantification of two proteases in mixture samples could satisfactorily be accomplished.
Mediating covalent crosslinking of single-chain nanoparticles through solvophobicity in organic solvents
Authors: Scheutz Georg M. , Elgoyhen Justine , Bentz Kyle C. , Xia Yening , Sun Hao , Zhao Junpeng , Savin Daniel A. , Sumerlin Brent S.
Published: July 2021

The photoinduced intrachain crosslinking of coumarin-containing copolymers in various organic solvents was mediated through the solvophobic effect, providing control over the reaction rate and the compaction of the final single-chain nanoparticles.
Pyridyl-functionalized spiro[fluorene–xanthene] as a dopant-free hole-transport material for stable perovskite solar cells
Authors: Yadagiri B. , Chowdhury Towhid H. , He Yulu , Kaneko Ryuji , Islam Ashraful , Singh Surya Prakash
Published: July 2021

We have developed a novel HTM named SPS-SPX-2TPA for perovskite solar cell applications. This HTM showed the best PCE of 17.39% and maintained 95% of their initial PCE even after 600 h. It is three times cheaper cost than the Spiro-OMeTAD HTM.
The dual effect of “inorganic fullerene” {Mo132} doped with SnO2for efficient perovskite-based photodetectors
Authors: Xu Xueying , Zhang Liming , Wang Ting , Li Yunjiang , Ji Tuo , Chen Weilin , Wang Chunlei , Lin Chunxia
Published: July 2021

A simple doping method was used to modify SnO2 with polyoxometalate {Mo132}. The doped composite material not only has a more matched energy level and improves conductivity, but can also improve the quality of the perovskite film grown on it.
Bio-synthesis of itaconic acid as an anti-crease finish for cellulosic fiber fabric
Authors: Boondaeng Antika , Suwanruji Potjanart , Vaithanomsat Pilanee , Apiwatanapiwat Waraporn , Trakunjae Chanaporn , Janchai Phornphimon , Apipatpapha Thanyachol , Chanka Napassorn , Chollakup Rungsima
Published: July 2021

A bio-synthetic process of itaconic acid production based from EPOFB, waste from oil extraction plant, was characterized and used for an anti-crease finish for cotton fabric.
Triazine-dibenzofuran-based n-type host materials for high-efficiency and long-lifetime green phosphorescent organic light-emitting diodes
Authors: Kim Dong Jun , Lee Sunhee , Lee Yong Hui , Jang Hyungkeun , Ahn Kwang-Hyun , Han Won-Sik
Published: July 2021

A series of triazine-dibenzofuran-based n-type host materials was developed for highly efficient green top-emitting PhOLEDs.
The kinetics of islet amyloid polypeptide phase-separated system and hydrogel formation are critically influenced by macromolecular crowding
Authors: Pytowski Lior , Vaux David J. , Jean Létitia
Published: July 2021

Many protein misfolding diseases (e.g. type II diabetes and Alzheimer's disease) are characterised by amyloid deposition. Human islet amyloid polypeptide (hIAPP, involved in type II diabetes) spontaneously undergoes liquid–liquid phase separation (LLPS) and a kinetically complex hydrogelation, both catalysed by hydrophobic–hydrophilic interfaces (e.g. air–water interface and/or phospholipids–water interfaces). Gelation of hIAPP phase-separated liquid droplets initiates amyloid aggregation and the formation of clusters of interconnected aggregates, which grow and fuse to eventually percolate the whole system. Droplet maturation into irreversible hydrogels via amyloid aggregation is thought to be behind the pathology of several diseases. Biological fluids contain a high volume fraction of macromolecules, leading to macromolecular crowding. Despite crowding agent addition in in vitro studies playing a significant role in changing protein phase diagrams, the mechanism underlying enhanced LLPS, and the effect(s) on stages beyond LLPS remain poorly or not characterised.We investigated the effect of macromolecular crowding and increased viscosity on the kinetics of hIAPP hydrogelation using rheology and the evolution of the system beyond LLPS by microscopy. We demonstrate that increased viscosity exacerbated the kinetic variability of hydrogelation and of the phase separated-aggregated system, whereas macromolecular crowding abolished heterogeneity. Increased viscosity also strengthened the gel meshwork and accelerated aggregate cluster fusion. In contrast, crowding either delayed cluster fusion onset (dextran) or promoted it (Ficoll). Our study highlights that an in vivo crowded environment would critically influence amyloid stages beyond LLPS and pathogenesis.
Small is beautiful: virus-like particles as vaccines
Authors: Jones Ian , Roy Polly
Published: July 2021

Virus-like particles (VLPs) are nanoscale structures that are mimics of virus particles themselves. They are stripped of any infection risk but can perform like viruses in some tasks although they are unable to spread. They are inherently safe and may offer additional advantages when compared to the viruses from which they derive. If they are produced by a recombinant route, as is very common, they can be modified by alteration of the sequences used to add functionality their parental versions did not possess, such as staying in a particular conformation, carrying different cargoes or targeting specific cells. It is probably true that VLPs are ascribed more promise than may ever be realized but their positive attributes are very real, they have already appeared as successful products and their potential is certainly far from exhausted.
A lipidomic view of SARS-CoV-2
Authors: Ebrahimi Kourosh H. , McCullagh James S.O.
Published: July 2021

The global pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which started in late 2019, has caused huge social and economic losses. A growing number of investigators are focusing on understanding the interaction of SARS-CoV-2 with host cellular processes to find therapeutic approaches. New data suggest that lipid metabolism may play a significant role in regulating the response of immune cells like macrophages to viral infection, thereby affecting the outcome of the disease. Therefore, understanding the role of lipid metabolism could help develop new therapeutic approaches to mitigate the social and economic cost of coronavirus disease 2019 (COVID-19).
Unravelling the impact of intrauterine growth restriction on heart development: insights into mitochondria and sexual dimorphism from a non-hominoid primate
Authors: Booz George W. , Massoud Gaelle P. , Altara Raffaele , Zouein Fouad A.
Published: July 2021

Fetal exposure to an unfavorable intrauterine environment programs an individual to have a greater susceptibility later in life to non-communicable diseases, such as coronary heart disease, but the molecular processes are poorly understood. An article in Clinical Science recently reported novel details on the effects of maternal nutrient reduction (MNR) on fetal heart development using a primate model that is about 94% genetically similar to humans and is also mostly monotocous. MNR adversely impacted fetal left ventricular (LV) mitochondria in a sex-dependent fashion with a greater effect on male fetuses, although mitochondrial transcripts increased more so in females. Increased expression for several respiratory chain and adenosine triphosphate (ATP) synthase proteins were observed. However, fetal LV mitochondrial complex I and complex II/III activities were significantly decreased, likely contributing to a 73% decreased LV ATP content and increased LV lipid peroxidation. Moreover, MNR fetal LV mitochondria showed sparse and disarranged cristae. This study indicates that mitochondria are targets of the remodeling and imprinting processes in a sex-dependent manner. Mitochondrial ROS production and inadequate energy production add another layer of complexity. Altogether these observations raise the possibility that dysfunctional mitochondria in the fetus may contribute in turn to epigenetic memory of in utero stress in the adult. The role of mitoepigenetics and involvement of mitochondrial and genomic non-coding RNAs in mitochondrial functions and nuclei–mitochondria crosstalk with in utero stress awaits further investigation.
Use of a Smartphone App for Cochlear Implant Patients With Tinnitus
Authors: Perreau Ann E. , Tyler Richard S. , Frank Victoria , Watts Alexandra , Mancini Patricia C.
Published: July 2021

Purpose

Smartphone apps for tinnitus relief are now emerging; however, research supporting their use and effectiveness is lacking. Research has shown that Tinnitus Therapy sounds intended for individuals with acoustic hearing provide relief to some patients using cochlear implants (CIs) with tinnitus. Here, we evaluated the use and acceptability of a smartphone app to help CI patients with tinnitus.

Method

Participants completed a laboratory trial (n= 19) and an at-home trial (n= 14) using the ReSound Tinnitus Relief app to evaluate its acceptability and effectiveness in reducing their tinnitus. During the laboratory trial, participants selected a sound that was most acceptable in managing their tinnitus (termedchosen sound). Word recognition scores in quiet were obtained before and after sound therapy. Participants were randomly assigned to one of two groups for the at-home trial, that is, AB or BA, using (A) the chosen sound for 2 weeks and (B) the study sound (i.e., broadband noise at hearing threshold) for another 2 weeks. Ratings were collected weekly to determine acceptability and effectiveness of the app in reducing tinnitus loudness and annoyance.

Results

Results indicated that some, but not all, participants found their chosen sound to be acceptable and/or effective in reducing their tinnitus. A majority of the participants rated the chosen sound or the study sound to be acceptable in reducing their tinnitus. Word recognition scores for most participants were not adversely affected using the chosen sound; however, a significant decrease was observed for three participants. All 14 participants had a positive experience with the app during the at-home trial on tests of sound therapy acceptability, effectiveness, and word recognition.

Conclusions

Sound therapy using a smartphone app can be effective for many tinnitus patients using CIs. Audiologists should recommend a sound and a level for tinnitus masking that do not interfere with speech perception.
Hierarchical distillation for image compressive sensing reconstruction
Authors: Lee Bokyeung , Ku Bonhwa , Kim Wanjin , Ko Hanseok
Published: July 2021

Compressive sensing (CS) is an effective algorithm for reconstructing images from a small sample of data. CS models combining traditional optimisation‐based CS methods and deep learning have been used to improve image reconstruction performance. However, if the sample ratio is very low, the performance of the CS method combined with deep learning will be unsatisfactory. In this letter, a deep learning‐based CS model incorporating hierarchical knowledge distillation to improve image reconstruction even at varied sample ratios. Compared to the state‐of‐art methods with all compressive sensing ratios, the proposed method improved performance by an average of 0.26 dB without additional trainable parameters.
Design workshop with farmers as a promising tool to support the introduction of diversifying crops within a territory: the case of camelina in northern France to supply a local biorefinery
Authors: Leclère Margot , Jeuffroy Marie-Hélène , Loyce Chantal
Published: July 2021

The development of local diversification value-chains requires the design and implementation of cropping systems adapted to a diversity of farms and the management of crops for which very little knowledge is available. In this article, using the example of camelina in northern France to supply a local oilseed biorefinery, we illustrate how (i) the realisation of a design workshop based on the formalization and sharing of local knowledge produced by a multi-stakeholder participatory approach, and (ii) the analysis, formalization and sharing of the outputs of this design workshop, are useful for supporting the introduction of a new species in a territory. In total, each of the nine farmers attending the workshop designed one (or two) proposal(s) to include and manage camelina adapted to their own situation. The precise description of these proposals and the explanation of the technical choices, the identification of the factors explaining the diversity of the proposals designed, as well as the inventory of the functions expected of the crop by the farmers, which are presented in this paper, constitute a set of elements that could also be used to support other farmers in the area who would like to introduce this new species into their cropping system.
A novel approach for solving stochastic problems with multiple objective functions
Authors: Kasri Ramzi , Bellahcene Fatima
Published: July 2021

In this paper we suggest an approach for solving a multiobjective stochastic linear programming problem with normal multivariate distributions. Our approach is a combination between a multiobjective method and a nonconvex technique. The problem is first transformed into a deterministic multiobjective problem introducing the expected value criterion and an utility function that represents the decision makers preferences. The obtained problem is reduced to a mono-objective quadratic problem using a weighting method. This last problem is solved by DC (Difference of Convex) programming and DC algorithm. A numerical example is included for illustration.
Conceptualizing the elements of research impact: towards semantic standards
Authors: Belcher Brian , Halliwell Janet
Published: July 2021

Any effort to understand, evaluate, and improve the impact of research must begin with clear concepts and definitions. Currently, key terms to describe research results are used ambiguously, and the most common definitions for these terms are fundamentally flawed. This hinders research design, evaluation, learning, and accountability. Specifically, the terms outcome and impact are often defined and distinguished from one another using relative characteristics, such as the degree, directness, scale, or duration of change. It is proposed instead to define these terms by the kind of change rather than by the degree or temporal nature of change. Research contributions to a change process are modeled as a series of causally inter-related steps in a results chain or results web with three main kinds of results: (i) the direct products of research, referred to as outputs; (ii) changes in the agency and actions of system actors when they are informed/influenced by research outputs, referred to as outcomes; and (iii) tangible changes in the social, economic, environmental, or other physical condition, referred to as realized benefits. Complete definitions for these terms are provided, along with examples. This classification aims to help focus research evaluation appropriately and enhance appreciation of the multiple pathways and mechanisms by which scholarship contributes to change.
Disciplinary power and practices of body politics: an evaluation of Dalit women in Bama’s Sangati and P. Sivakami’s The Grip of Change through Foucauldian discourse analysis
Authors: Ghosh Aditya
Published: July 2021

Through a Foucauldian reading of Bama’s Sangati (2005) and P. Sivakami’s The Grip of Change (2006a, 2006b), this paper attempts to delineate the permeation and maintenance of disciplinary power in the social structure and assertion of patriarchal politics in the subjugation of Dalit female bodies. The detrimental politics of patriarchal discourse, the paper argues, degrades the existence of Dalit women, and excludes them from the equation of power relations by delimiting their access to society’s productive resources and restricting their sexuality. Disciplinary power, which acts as a patriarchal tool, prescribes acceptable gestures and required behaviour, and through constant surveillance normalizes a dominant male order. It reduces Dalit women’s existence into an amorphous property, readily mutilated and moulded under the whims of a phallocentric order. Discursive practices further constitute practices of body politics, making the female body an object of active site of political struggle. The paper studies Sangati and The Grip of Change as literary exemplars to demonstrate how disciplinary power, as underscored by Foucault’s discourse analysis, intervenes and determines the life of Dalit women. It not only lays bare the covert body politics of patriarchy with the unfiltered depiction of women’s exploitation and atrocities, but also represents a paradigm shift by advocating ways of emancipation for Dalit women.
Equations of State for the Thermodynamic Properties of Three Hexane Isomers: 3-Methylpentane, 2,2-Dimethylbutane, and 2,3-Dimethylbutane
Authors: Gao Kehui , Wu Jiangtao , Lemmon Eric W.
Published: July 2021

Equations of state for three hexane isomers, 3-methylpentane, 2,2-dimethylbutane, and 2,3-dimethylbutane, have been developed based on experimental thermodynamic property data from the literature. These equations are explicit in the Helmholtz energy with independent variables of temperature and density. The temperature, pressure, and density validity ranges of the equations of state were determined by the available measured data for these three fluids. The uncertainties in densities, vapor pressures, saturated liquid and vapor densities, and caloric properties were estimated by comparisons with experimental data of these properties. The behavior of various thermodynamic properties was analyzed to assess the quality of the equations of state. Physically correct behavior within the region of validity and at extremely high temperatures and pressures, and temperatures far below the triple-point temperature, was obtained through fitting multiple constraints of various properties.
Temperature gradient and transport of heat and charge in a semiconductor structure
Authors: Titov Oleg Yu. , Gurevich Yuri G.
Published: July 2021

A detailed analysis of the influence of thermal nonequilibrium on transport in semiconductors was carried out. It is shown that the transport of heat and electricity in bipolar semiconductors are interdependent and self-consistent. In a general case, the distribution of the temperature in homogeneous semiconductors cannot be constant or a linear function with respect to the coordinate even in a linear approximation. The roles of nonequilibrium charge carriers and the recombination in the heat transport are established.
Effect of magnetic field on the modulated spin structure of terbium manganite film
Authors: Chupis I. E.
Published: July 2021

The first-harmonic approximation of the Ginzburg–Landay theory was used to analyze the influence of magnetic field H along the y axis (modulation direction of manganese spins) in incommensurate AFM phases in the orthorhombic TbMnO3 film. It was shown that an increase in magnetic field and a decrease in the film thickness lead to the decrease in the Neel temperature. The dependence of the Neel temperature on magnetic field in the TbMnO3 film was obtained. The boundary lines between modulated AFM phases in magnetic field are changed weakly besides some increase in the temperature Tc = 28 K at H = 0. It means the conservation of the colossal magnetoelectric effect of the “polarization flop in magnetic field” in the manganite terbium films up to 6 nm thickness. Therefore, such TbMnO3 films (3 periods of the spin cycloid) can become a basis of future nanotechnology of the magnetoelectric devices.
Gyrotropic superlattice as a transformer of light polarization
Authors: Makarov N. M. , Melnyk S. S. , Usatenko O. V. , Shmat’ko A. A. , Yampol’skii V. A.
Published: July 2021

We suggest a novel approach to predict and clarify the transformation of an arbitrarily polarized wave into two circularly polarized ones, based on the peculiar features of their transmission and reflection from a stack with regularly arranged gyrotropic layers. In spite of the fact that in the Faraday geometry gyrotropic media possess four electromagnetic eigenmodes, we have managed to modify the problem to be analytically resolved within the conventional transfer-matrix method. As a result, we have obtained and analyzed the dispersion relation, as well as the transmission and reflection coefficients, which are applicable for any elliptic polarization of a wave irradiating a gyrotropic superlattice with finite number of unit cells. It is shown that there exists a wide range of wave frequency and magneto-optical parameter (proportional to external dc magnetic field) inside of which the wave of given circular polarization is perfectly transmitted, while the wave with the opposite circular polarization is completely reflected. Thus, under certain conditions, the incident plane wave (taken as an appropriate example) splits up into the transmitted and reflected circular waves with mutually inverse rotations. We indicate conditions when a relatively small variation of the magnetization can reverse the polarizations mentioned above.
Instability of the pulsar surface in strong constant fields and generation of additional components due to combination scattering
Authors: Kontorovich V. M.
Published: July 2021

Periodic structures on polar caps, arising due to instability of the pulsar surface in a strong magnetic field, can be responsible both for the appearance of additional components in pulsar radiation and the formation of sickle shaped hot spots arising as a possible result of Mandelstam–Raman scattering of the reflected radiation by returned positrons.
Magnetic susceptibility of crystals with crossing of their band-contact lines
Authors: Mikitik G. P. , Sharlai Yu. V.
Published: July 2021

The orbital magnetic susceptibility produced by electron states near a crossing point of two band-contact lines in a crystal is studied theoretically. It is shown that this susceptibility can have an unusual dependence on the Fermi level and can change noticeably with the temperature when the Fermi level is in the vicinity of the crossing point. These features of the magnetic susceptibility can be useful in detecting the crossing points in crystal. The obtained results explain the well-known temperature dependence of the magnetic susceptibility of V3Si.
Prediction of cutting force in ultra-precision machining of nonferrous metals based on strain energy
Authors: Wang Ying , Yuan Zewei , Wu Tianzheng , Yan Heran
Published: July 2021

The effects of the nonuniform cutting force and elastic recovery of processed materials in ultra-precision machining are too complex to be treated using traditional cutting theories, and it is necessary to take account of factors such as size effects, the undeformed cutting thickness, the tool blunt radius, and the tool rake angle. Therefore, this paper proposes a new theoretical calculation model for accurately predicting the cutting force in ultra-precision machining, taking account of such factors. The model is first used to analyze the material deformation of the workpiece and the cutting force distribution along the cutting edge of a diamond tool. The size of the strain zone in different cutting deformation zones is then determined by using the distribution of strain work per unit volume and considering the characteristics of the stress distribution in these different deformation zones. Finally, the cutting force during ultra-precision machining is predicted precisely by calculating the material strain energy in different zones. A finite element analysis and experimental data on ultra-precision cutting of copper and aluminum are used to verify the predictions of the theoretical model. The results show that the error in the cutting force between the calculation results and predictions of the model is less than 14%. The effects of the rake face stress distribution of the diamond tool, the close contact zone, and material elastic recovery can be fully taken into account by the theoretical model. Thus, the proposed theoretical calculation method can effectively predict the cutting force in ultra-precision machining.
Effects of solvent composition on ionization and fragmentation within the solution-cathode glow discharge
Authors: Walton Courtney L. , Schwartz Andrew J. , Shelley Jacob T.
Published: July 2021

Recently, solution-electrode glow discharges (SEGDs) have shown great utility as ionization sources for mass spectrometry (MS). The solution composition of SEGD electrodes is pivotal to their performance as it influences analyte-ion formation. The performance of electrospray ionization is heavily dictated by spray-solution composition, which can alter ionization efficiency and pathways. While SEGDs produce Taylor cones similar to electrospray ionization, the influence of solution-electrode composition on molecular-ion formation has not been studied. Here, we examine how additives to an atmospheric-pressure solution-cathode glow discharge (SCGD) influence molecular ionization and fragmentation. The impact of several additives to the acidic solution of an SCGD ionization source was evaluated based on mass-spectrometric performance. Addition of methanol increased molecular- and fragment-ion signals for peptide angiotensin II. This effect is likely due to improved desolvation and a greater interaction of analyte molecules with glow-discharge species. Several high-boiling-point reagents were tested to examine changes in the ion signal, the average charge state, and the degree of fragmentation. Overall, these additives inhibited fragmentation but significantly lowered intact molecular-ion signals. Interestingly, loss of fragment ions trended with the boiling point of the reagent used. We hypothesize that analyte molecules become trapped in droplets produced at the solution-cathode surface. These droplets do not fully desolvate before escaping the discharge region, sparing analyte molecules from fragmentation. For low volatility additives, droplets do not desolvate, even as they enter the heated MS, which yields a loss in molecular ions. The changing composition of the SCGD solution alters analytical performance, but also provides insight into analyte ionization and fragmentation processes.
Two-step current-temperature-induced electrical and optical modifications in VO2 films around the metal–insulator transition
Authors: Manousou Dimitra K. , Gardelis Spiros , Calamiotou Maria , Likodimos Vlassis , Syskakis Emmanuel
Published: July 2021

We report on two-step current-induced effects on the electrical, optical, and structural properties of VO2 films around the Metal–Insulator Transition (MIT) in synergy with ambient temperature (T). Simultaneous electrical resistance and transmittance measurements of VO2 semitransparent thin films as a function of T show that the electric current modifies the MIT that takes place in two steps: an abrupt change that increases upon increasing current, implying the formation of larger metallic domains within the current path, accompanied by a smoother change that follows the temperature change. Resistance measurements of thicker bulk-like VO2 films have been also investigated exhibiting similar two-step behavior. By monitoring the specimen temperature (To) during resistance measurements, we show that the abrupt resistance step, accompanied by instantaneous heating/cooling events, occurs at temperatures lower than TMIT and is attributed to current-induced Joule heating effects. Moreover, by monitoring To during current–voltage measurements, the role of T in the formation of two-step current modified MIT is highlighted. X-ray diffraction with in situ resistance measurements performed for various currents at room temperature as a function of To has shown that the current can cause partially MIT and structural phase transition, leading to an abrupt step of MIT. The formation of a rutile metallic phase of VO2 under high applied currents is clearly demonstrated by micro-Raman measurements. By controlling current in synergy with T below TMIT, the VO2 film can be driven to a two-step current-induced MIT as gradually a larger part of the film is transformed into a rutile metallic phase.
Light absorption by interacting atomic gas in quantum optical regime
Authors: Sizhuk Andrii S. , Dorfman Konstantin , Ooi C. H. Raymond
Published: July 2021

Quantum optical theory of absorption properties of interacting atoms is developed. The concept of local absorptance is introduced as a derivative of the logarithm of intensity with respect to the distance in the vicinity of a given spatial point and a moment of time. The intensity is represented by the quantum and statistically averaged normal product of creation and annihilation operators of the electromagnetic field. The development of an analytical method of the estimation for the kinetic and optical parameters for the system is proposed here. The calculation method of the absorption coefficient includes thermal atomic motion, Doppler effect, and the short-range interaction between atoms. The absorption coefficient explicitly takes into account the quantum nature of the optical field. The ability of the system to absorb or emit quanta is quantitatively expressed through the special form of interaction integrals. The specific form of integrals results from the structure of the quantum brackets. The interplay between the collective (virtual photon exchange) and binary (optically induced inter-particle bonding) processes determines the system behavior. The spectral profile of the local absorption coefficient for different atomic densities and time intervals is simulated for realistic parameters.
Superconductivity in highly doped diamond: Role of group III and V impurities
Authors: J. R. Costa F. , S. de Almeida J.
Published: July 2021

This study comprises an investigation of the superconductivity in highly doped diamond, comprising elements from groups III and V acting as acceptor and donor impurities, respectively, within the virtual crystal approximation. Calculations of the electron–phonon coupling were carried out for each case, enlightening the different aspects arising from different doping elements and their consequent impact on the superconducting critical temperature. These calculations indicated that among the hole-doped cases the electron–phonon coupling is strongly related to the optical phonons of the lattice. Regarding the electron-doped systems, it was observed that the coupling had contributions from both optical and acoustic vibrations, leading to high estimates for the critical temperature. Through the comparison between these opposing scenarios, several distinctions between the electron- and hole-doped cases became evident, implying that the mechanisms of superconductivity in doped diamond relate directly to the nature of the impurity added to the system. These results provide further evidence that the electronic and dynamic changes arising from the electron doping of a diamond may lead to superconductivity in high temperatures.
Characterization of a radio-frequency inductively coupled electrothermal plasma thruster
Authors: Lafleur T. , Corr C. S.
Published: July 2021

A radio-frequency (RF) inductively coupled electrothermal plasma thruster operating with argon is experimentally characterized for different mass flow rates, RF powers, and propellant injection configurations. Depending on the propellant mass flow rate, significant neutral gas heating is observed with effective stagnation temperatures around 2000 K (giving a maximum estimated thrust and specific impulse of about 100 mN and 125 s, respectively) for absorbed powers between 300 and 500 W. A self-consistent theoretical discharge model is developed and used to study the basic physics and operation of RF electrothermal thrusters, and predictions of the gas temperature are in good agreement with experimental measurements. The model identifies primary power inefficiencies as electron-neutral excitation losses and neutral gas heat losses to the thruster walls. Both experimental and theoretical results indicate that a relatively high stagnation pressure (of the order of 100 Torr or higher) is critical for high performance. For pressures significantly below this the electron-neutral collisional power transfer is too low to effectively heat the neutral gas.
Maximizing and minimizing the boundary scattering mean free path in diameter-modulated coaxial cylindrical nanowires
Authors: Song Yingru , Wehmeyer Geoff
Published: July 2021

The thermal conductivity (k) of semiconducting nanomaterials is influenced by the geometry-dependent phonon boundary scattering mean free path (ΛBdy). Although prior work has calculated ΛBdy of periodically corrugated rectangular nanowires and used these results to study phonon backscattering in nanomaterials, ΛBdy remains unknown for recently fabricated periodic coaxial cylindrical nanowires. Here, we use phonon ray tracing simulations to comprehensively study the effect of geometric parameters on ΛBdy in coaxial cylindrical nanowires. We find that for a fixed smaller cylinder diameter (D1) and cylinder length ratio, ΛBdy of periodic nanowires can be maximized or minimized via geometric control of the pitch (p) and larger cylinder diameter (D2). Our simulations show that saturated phonon backscattering for small pitch ratio (pr) nanowires gives rise to a minimum in ΛBdy/D1 at pr near unity, while the maximum in ΛBdy/D1 for large pr nanowires can be understood using a simple thermal resistor model for two individual nanowires in series. Combining our ΛBdy calculations with analytical phonon dispersion and bulk scattering models, we predict that k of periodic silicon nanowires with fixed D1can be tuned by up to 34% in the boundary scattering dominated regime by modifying D2 and p and that variations as large as 135% can be observed in the normalized thermal conductance. Our results provide insight into geometry-dependent phonon backscattering and can be used to predict k of periodic cylindrical nanowires over a range of temperatures and geometric lengthscales.
Polarization singularities and Möbius strips in sound and water-surface waves
Authors: Bliokh Konstantin Y. , Alonso Miguel A. , Sugic Danica , Perrin Mathias , Nori Franco , Brasselet Etienne
Published: July 2021

We show that polarization singularities, generic for any complex vector field but so far mostly studied for electromagnetic fields, appear naturally in inhomogeneous yet monochromatic sound and water-surface (e.g., gravity or capillary) wave fields in fluids or gases. The vector properties of these waves are described by the velocity or displacement fields characterizing the local oscillatory motion of the medium particles. We consider a number of examples revealing C-points of purely circular polarization and polarization Möbius strips (formed by major axes of polarization ellipses) around the C-points in sound and gravity wave fields. Our results (i) offer a new readily accessible platform for studies of polarization singularities and topological features of complex vector wave fields and (ii) can play an important role in characterizing vector (e.g., dipole) wave–matter interactions in acoustics and fluid mechanics.
The non-isothermal Bödewadt problem applied to an advanced plasma centrifuge
Authors: Whichello J. V. , Borisevich V. D. , Potanin E. P.
Published: July 2021

Several valuable isotopes used in medicine, industry, and science cannot be separated by a gas centrifuge with a driven mechanical rotor due to the lack of a suitable working gas that has a sufficiently high vapor pressure at room temperature. Such isotopes are typically produced by more costly separation processes. An advanced plasma centrifuge (PC) has been proposed that can separate specific isotopes at a lower cost. The PC achieves increased separation performance by the excitation of an axial counterflow in the plasma medium. In this work, we consider the non-isothermal Bödewadt problem for the PC with thermally driven axial circulation created by cooling one end of the PC's separation chamber. Due to the imbalance between the centrifugal force and the radial pressure gradient, we show that a secondary flow appears, which is imposed on the medium's rotation motion. The effect is analogous to the classical Bödewadt problem, where a rotational flow decelerates over a fixed surface.