bluuebunny/crossref_metadata_2025 huggingface dataset:
Opportunities for using biologically active substances Rhodiola rosea L. in the production of functional food with consideration for antimicrobial activity
Authors: Zaushintsena Alexandra , Babich Olga , Bryukhachev Evgeny , Milenteva Irina , Starcev Anton
Published: June 2020

Biologically active substances extricated by extraction of water and 40% ethyl alcohol from rootstalks of Rhodiola rosea L.: gallic acid, forms of rosovin and salidroside have been studied. Thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) were used during the research. Determination of antimicrobial activity was performed by agar diffusion method (OFC.1.2.4.0010.15) [8]. The method is based on the evaluation of inhibition of the growth zone of testing cultures of microorganisms by certain concentrations of biologically active substances (BAS). String formed bacteria (8 strains), cocci bacteria (3) and fungal (4) microorganisms, bifidobacterium (10 strains) were used as testing cultures. Various responses of microorganisms to exposure by biologically active substances have been determined. Gallic acid and salidroside in the aqueous phase have the maximum inhibitory property to rod bacteria and coccoid microorganisms. Post-antibiotic effect is shown in rozovin. Salidroside in the butanol phase is more neutral to most microorganisms, with the exclusion of: Acinetobacter baumannii, Pseudomonas aeruginosa, Bacillus cereus and Staphylococcus aureus. The lack of a clearly expressed reaction of BAS to bifidobacterium, most probably, gives the possibility of their use in the development of functional products of a new generation. However, first of all, it is required to organize a special experiment on the structure of the introduction of the studied components into the lactoserum. Next, determine the content of BAS in the derived product, the reaction of bifidobacterium admitted for use in biotechnology, and a standard set of microbiological strains. Gallic acid is suggested to be introduced in applied studies to explore as a target immunomodulator of resistance to the listed microflora and to develop an effective form of a new product.
Study of the spectra of asymmetric triazines with growth-stimulating activity
Authors: Builova Evgenia , Kuznetsova Elena , Rolnik Lyubov , Shaikhullin Irek , Aminova Gulia
Published: June 2020

Derivatives of nitrogen-containing heterocycles, in particular compounds of symmetric and asymmetric triazines, are widely used in agriculture as regulators of plant growth and development. Among the derivatives, the most well-known use of symmetric derivatives, however, they are difficult to biodegrade and accumulate in the soil, and as a result in the plants themselves. Therefore, asymmetric triazines, which are easily decomposed in the environment, are more promising in practical terms. Currently, it is very important to use environmentally friendly plant growth and development regulators that do not contain impurities, so much attention is paid to the identification of synthesized compounds of asymmetric triazines with a substituent in position 5 using UV, IR and Mass spectroscopy.
The problem of introduction of rare and endangered plants of the middle Urals’ flora
Authors: Karpukhin M. Y. , Abramchuk A. V.
Published: June 2020

The problem of gene pool protection of wild plant species has gained a special relevance in modern times. In connection with the growth of population there is an increase in economic activity of human beings and their active influence on nature: wild lands plowing, overpasses plotting, construction of new and widening the boundaries of existing settlements. In addition, intensive harvesting of plants as medicinal, decorative, food, forage, etc is in progress. All this has a negative effect on the condition of wild plants: their stocks are declining, and some species are disappearing at all. A number of plants such as: spring adonis (Adonis vernalis L.), martagon lily [Liliumpilosisculum(Freyn)) Miscz,L.], butterfly orchid [Platantherabifolia(L.) Rchb], PaeoniaanomalaL. , rosewort (Rhodiolarosea L.) in their status, they belong to the group of rare and endangered species, they are listed in the Red Book of the Middle Urals, and their conservation requires introduction.

The study found that the species studied are culturally resistant, adapting well to new conditions. During the growth process, they went through all phenological phases, ending the development cycle with the fruiting phase with seed formation. Seeds with high enough sowing properties was provided by martagon lily, for which self-seeding is characteristic; low germination of seeds is noted in Rhodiolarosea L. and Platantherabifolia (L.) Rchb.
New methods in genotype diagnostics of small-fruit crops for intensive gardening
Authors: Panfilova Olga , Tsoy Mikhail , Kalinina Olga , Knyazev Sergey
Published: June 2020

Physiological and morphological studies of red Russian and foreign breeding red currant varieties were carried out for establishing intensive plantings and introduction. Varieties Dana, Niva, Vika, Hollandische Rote are yielding, highly resistant and promising for introduction and industrial cultivation, during dry periods they are able to regulate metabolism through changing indicators of water balance (water deficit, fractional composition of water) and photosynthetic apparatus of leaves (leaf lamina area). Using Natali, Shchedraya and Jonkheer Van Tets varieties in production is possible with application of artificial irrigation. Selyanochka variety is most affected by weather conditions and is recommended to be grown in temperate climate area. Physiological and morphological methods of research allow to diagnose the genotypes resistance of garden crops to growing period abiotic factors at the early stages of plant development, they are confirmed by field observations and are promising in diagnosis for establishing intensive gardens and berry-fields.
Plant-based food supplement developing and studying its role in optimizing carbohydrate and fat metabolism of people with diabetes under conditions of agriculture digitization
Authors: Kalimullin M.I. , Sadi S.S. , Tokhiriyon B. , Poznyakovsky V.M. , Andrievskikh S.S.
Published: June 2020

Under conditions of digital economy, in particular, agriculture and food industry, specialized food products, including biologically active food supplements produced from natural raw materials, are increasingly used to improve nutrition and health, and to maintain quality of life. These products are affordable and efficient in coping with metabolism disorders caused by different diseases. Taking all these factors into account the authors developed a pant-based food supplement aimed at improving metabolism of people with type 2 diabetes. The composition of this specialized product is scientifically based in terms of its ingredients and their active substances biochemical and synergetic properties. The innovative production technology of this biologically active food supplement involves pressing its main ingredients and auxiliary substances into tablets. The tablet form provides accurate dosage, convenient packaging and storage, reliable film coating, which ensures tablet hardness and protection from aggressive exposure. The food supplement properties have been determined, including its nutritional value and functional properties. One tablet includes: ascorbic acid – 8.6 mg, chromium -0.1mg, zinc – 2.3 mg, flavonoids – 10mg, tannins – 20 mg, manganese – 0.8mg. Clinical trials proved the supplement efficacy and functional properties. People with type 2 diabetes took 1 tablet of phyto-complex twice a day alongside sugar-lowering drugs. After one month they demonstrated lower levels of blood glucose, total cholesterol and triglycerides as well as better overall health and lower body mass index. The obtained data clearly indicate better pancreas functions, improved microcirculation, carbohydrate and fat metabolism normalizing. The article also provides recommendations of the supplement intake for people with type 2 diabetes and glucose tolerance disorders.
Scientific support for innovative development of wheat bread long-term storage production
Authors: Zavorokhina Natalia , Pankratyeva Natalia , Goncharova Nadezhda
Published: June 2020

Nowadays in the context of innovative development the bread intended for long-term storage is necessary in hard-to-reach areas of Sverdlovsk region, participants of expeditions, workers of logging, geological parties, etc. Taking into account the constant demand for such products, it is necessary to develop new approaches to their creation.The aim of the study was the development of long-term storage bread from wheat flour, preserving consumer characteristics throughout the shelf life.The synergism of betulin,nisin and ascorbic acid was studied for the first time when they are used together to inhibit potato bread disease (hereinafter CBH). It is proved that the use of additives, including 0.015% nisin together with 0.005% betulin to the mass of flour increases the shelf life of wheat bread up to 7 days since betulin inhibits CBH, nisin inhibits the development of mold under pH conditions in the range of 5.5-6.5.For the first time, a technique is proposed for producing betulin nanosuspension with a high degree of dispersion. The effect of betulin nanosuspension with emulsifiers of calcium lactylate, polyglycerol fatty acid esters, lecithin on the inhibition of CBH and an increase in the shelf life of wheat bread was studied.
Towards an automated economic assessment of innovative projects for the production of tonic Beverages
Authors: Kotova T. V. , Medvedev A.V. , Solopova A. N.
Published: June 2020

Over the past five years, in the country and in the world there has been an increase in the production and consumption of non-alcoholic tonic drinks (NTD). Representatives of various scientific schools are developing new NTD formulations. The regional characteristics of the used plant raw materials with a tonic effect are taken into account. The priority task of the food industry is to carry out activities aimed at making healthy food products, taking into account not only the traditions and habits of the population, but also the cost-effectiveness of introducing them into production. The paper considers the requirements of regulatory documentation for raw materials, elaborates the technological scheme of NTD production, describes the requirements for labeling and packaging of the finished drink. Introducing new technologies into production is an expensive process. The aim of the work is a preliminary automated assessment of the economic efficiency of an investment project for the production of NTD based on new recipes. The specified assessment is carried out from the point of view of traditional indicators of project efficiency, using the Karma optimization software package, which allows identifying the economic potential and finding the optimal characteristics of investment, production, financial activities of investment and production projects. The influence of the key indicator of the project (the market price of a unit of production) on the main indicators of the effectiveness of the investment project is studied. The life cycle is analyzed and the economic potential of the investment project is revealed through the use of an optimization mathematical model. The dependence of the net present value of the project on the planning horizon is described with a variation in the market unit price parameter. High characteristics of the economic efficiency of the investment project are obtained. Practical recommendations are given on sales markets, production technology, implementation of investment projects related to the production of NTD «Wild Cat».
Information and measuring system for operational monitoring of soil moisture and temperature
Authors: Blokhin Yuri , Blokhina Svetlana , Dvirnik Anna , Belov Andrei , Makushin Andrei
Published: June 2020

The structure of the wireless sensor network (WSN) for operational monitoring of soil moisture and temperature on the agricultural field with high accuracy is considered in the article. The evaluation of wireless sensor networks' technical capabilities for agricultural applications is given; the advantages and disadvantages of their use in the field conditions are noted, taking into account the influence of different factors on the quality of communication. To solve the problems of radio communication in the soil and deploying a sensor device completely below the ground surface, the prototype model of a sensor node with a retractable antenna has been developed. Sensor nodes were communicated via the ZigBee protocol and the integrated spatial attribute information was transmitted into the database.
Socio-economic aspects of bank lending to agriculture
Authors: Serebrennikova Anna I. , Mikryukov Aleksey V. , Tchilimova Tatyana A.
Published: June 2020

The article is devoted to the socio-economic aspects of banks ' activities in relation to agricultural lending. The contextual background of the study is the social significance of agriculture for the country in terms of food security and the formation of a stable standard of living of the population. The purpose of the study was to reach the essential understanding of the social aspects of the Bank's activities by considering the social functions of the Bank in the lending process. The article considers the composition of credit subjects and gives a brief description of them. The activity of the State as a regulator of credit relations and a full participant in lending is emphasized. The essential understanding of the bank 's social functions in the context of solving the state 's social task of financing agriculture through the mechanism of concessional lending has been expanded. Conclusions are made about the leading role of the state in the formation of the mechanism of interaction between the Bank and the borrower with the strengthening of social functions of the Bank.
Scientific justification of the formula composition of biotechnological form of BAA with directed functional properties
Authors: Bulashko О. N. , Kotova T. V. , Poznyakovsky V. M.
Published: June 2020

For the prevention and treatment of gastrointestinal diseases, the microbiome of the living organism is of great importance. The human health depends on quantitative and qualitative composition of microbiota. Under the influence of factors of internal and external environment there is a change in the indigenous microflora. For correction, prevention and regulation of intestinal microbiocenosis within the framework of the biotechnology program, biologically active additive (BAA) is proposed, the main components of which are selective biomass bacteria, prebiotics, peptide ultralisates. As substances that perform the function of coenzymes, thiamine (vitamin B1) and pyridoxine (vitamin B6) are used in the production of this additive. The novelty of the technology is the composition and structure of solid gelatin capsules, ensuring maximum safety of biologically active ingredients and delivery of them to cells. Regulated quality indicators have been established. Sanitary-hygienic and sanitary-toxicological indicators of the BAA comply with the requirements of TR CU 021/2011 “On safety of food products”. Clinical approbation of the developed additive was carried out by volunteers with detected disorders of intestinal microbiota. BAA was taken 1 capsule 2 times a day in conjunction with other drugs regulating bowel biocenosis. At the end of dietary therapy, the microbiota recovery was observed in 90% of cases. Technical documentation has been approved for the new product, recommendations for application have been developed.
Assessing the contribution of subsistence economy in income generation of rural households in Yakutia
Authors: Gavrilyeva Tuyara , Naberezhnaya Anna , Ivanova Marina
Published: June 2020

Traditional economic activity is a significant part of non- observed economy sustaining in regions with a large share of rural population. Non-transparency of subsistence economy hampers assessment of its contribution to goods and services production, the number and income levels of self-employed. The paper summarizes a study of contribution of private subsidiary plots and other forms of traditional economic activity (hunting, fishery, gathering) in rural household incomes and self- employment in Yakutia based on a representative sociological survey of 2017-2019. The share of in-kind income in household budgets estimated by the authors averages 15.7%, partly compensating for cash income deficit and helping alleviate poverty problem in the region.
Institutionalization of planetary management boundaries
Authors: Ryazanova Olesya , Kashtelian Тaisiya , Zolotareva Vera , Ryabokon Anna
Published: June 2020

Within the framework of the problem of institutionalization of planetary management boundaries, planetary property and planetary rent are considered as the idea of radical institutional -economic innovation designed to form the economy of optimal resource use and equitable distribution of world income. The authors use a systemic approach that emphasizes the importance of institutional analysis of rent-oriented behavior. The relevance and timeliness of theoretical and methodological approaches of the planetary management boundaries paradigm for all sectors of the economy, including agro-industrial complex. The relationship of agro-industrial and forest complexes in the mechanism of use of planetary land resources is traced. Particular attention is paid to forest rents as a value positioned in the aspect of the global bioeconomic system and plays an important role in the process of its evolution. The authors note the inevitability of conflicts of rent relations on the planetary scale, the solution of which requires the unification of efforts of the entire global scientific community.
Non-tax payments as a deterrent of AIC innovative development
Authors: Gordienko Mikhail
Published: June 2020

The article covers the fiscal relations that are developing in the sphere of agro-industrial complex of Russia. In this economy sector, as in all others, non-tax payments are charged, which are not officially submitted in the Tax Code of the Russian Federation, but are obligatory for payment to various control and monitoring bodies. This legal conflict results that non-tax payments are not taken into account in the calculation of the fiscal burden of economic entities, the reason why it can increase uncontrollably, thus limiting the company’s profitability. This indicator directly determines the amount of its own available financial resources, which the company can direct to reinvest in its own innovative development. In this connection, the article analyzes the normative legal field of non-tax payments and the composition of the of the Russian budget revenue register, which includes all the main non-tax payments. A selection of profile payments administered and collected from companies in the agro-industrial complex of the Russian Federation is carried out. Qualitative and quantitative indicators of non-tax payments of the agro- industrial complex of Russia in the period of 2018-2021 are studied on a sample basis. Conclusions are made regarding the presence of fiscal burden of non-tax payments being a limiting factor of investment policy in the innovative development sphere of companies of the Russian agro- industrial complex.
Assessment of innovative development of the regional economy by multiple analysis methods
Authors: Salimova Guzel , Ableeva Alisa , Nigmatullina Gulnara , Galimova Aigul , Bakirova Ramzilya
Published: June 2020

The article studies the system of indicators characterizing the innovative development of regions. A hierarchical classification of the subjects of the Volga Federal District of the Russian Federation by indicators characterizing the results of innovative activities of organizations, including agricultural enterprises, has been performed. A comparative analysis of the regions by the level of innovative development is carried out. Regularities are revealed, prospects for further development are determined. For each cluster, promising areas of innovative economic development are identified. The connection of science and production, leading to innovative development, is shown.
Risks of environmental opposition to the investment projects implementation
Authors: Vidrevich M.B. , Pakhalchak G.Yu.
Published: June 2020

Investment activity plays a significant role in achieving the strategic goals of the development of society, and has a significant impact on the state of the environmental and economic system. Recently, quite often, the interests of various groups related to the preservation of the environment come into conflict with the need for economic development, and hence the impossibility of investing in this development. In this case, potential or real investors lose the money invested. The purpose of the research is to consider the features of environmental and social risks of implementing investment projects, to consider the features of social and environmental risks and to show the need to take into account social and environmental risks for the implementation of investment projects, as well as suggest ways to minimize them. It is shown that the effectiveness of the implementation of investment projects and the reduction of possible losses of investors can be achieved by real consideration of social and environmental risks. Some instruments to reduce the risks of implementing investment projects are proposed.
Conceptual approaches to improvement of the sustainability management mechanism of the agrarian sphere development of the region in the Russian Federation
Authors: Kalitskaya Victoria , Pustuev Andrey , Rykalina Olga , Perminova Irina
Published: June 2020

In the framework of the study, the authors consider conceptual approaches to improve the management system of agrarian sphere development of regions in the realities of this industry functioning in the Russian Federation. Agrarian sphere is shown in aspects of socio-economic territorial system with its subsystems. The transition mechanisms of the agrarian sphere to the rails of sustainable development due to the choice of priority development directions within the life cycle are presented. The necessity of applying an integrated approach to the solution of industrial and social problems of the agricultural sector of the country is proved and reasoned.
Spin transition properties of metal (Zn, Mn) diluted Fe(phen)2(NCS)2 spin-crossover thin films
Authors: Saha Saroj , Mandal Swapan K.
Published: June 2020

We report here the effect of metal (Zn and Mn) dilution on the spin transition of Fe(phen)2(NCS)2 thin film spin-crossover (SCO) complex. The SCO complexes are deposited on glass and indium-tin-oxide (ITO) coated glass by dip-coating technique. The growth of the films is clearly confirmed by the appearance of the sharp optical absorption band at 521–540 nm corresponding to 1A1g to 1T1g ligand field absorption of the SCO complex. Although the microstructure of the films remains unaffected by metal dilution, substitution of Fe(II) by either Zn(II) (diamagnetic) or Mn(II) (paramagnetic) results in subtle changes in the bonding environment of the host metal as inferred form X-ray diffraction and Raman studies. The high spin to low spin (or vice versa) transition can be triggered either by electric field or magnetic field as revealed in the measured current (I)–voltage (V) profile or magnetization data of the films. The data further shows the effect of metal dilution on the spin transition temperatures(T1/2), produced hysteresis loop width and loop area, which are the crucial parameter for fabricating spin-based room temperature switching devices.
La psychosomatique kleinienne : Angel Garma 1904-1993
Authors: Chemouny Jacquy
Published: June 2020

Les contributions d’Angel Garma à la psychanalyse ont été nombreuses et variées. Il a surtout étudié trois domaines : le rêve, le traumatisme et la psychosomatique. Si les deux premiers sujets sont souvent mentionnés, celui de la psychosomatique a par contre peu retenu l’attention. Cet article se propose de présenter les cadres conceptuels qui président à ses travaux psychosomatiques. Nous en dégageons trois : les désordres psychosomatiques sont soit l’expression d’une personnalité singulière soumise à une dynamique psychique centrée sur l’existence de conflits libidinaux, soit en relation avec des objets intériorisés issus des relations précoces avec la figure maternelle, soit refoulés.
Semi-annual, annual and Universal Time variations in the magnetosphere and in geomagnetic activity: 2. Response to solar wind power input and relationships with solar wind dynamic pressure and magnetospheric flux transport
Authors: Lockwood Mike , McWilliams Kathryn A. , Owens Mathew J. , Barnard Luke A. , Watt Clare E. , Scott Chris J. , Macneil Allan R. , Coxon John C.
Published: June 2020

This is the second in a series of papers that investigate the semi-annual, annual and Universal Time (UT) variations in the magnetosphere. We present a varied collection of empirical results that can be used to constrain theories and modelling of these variations. An initial study of two years’ data on transpolar voltage shows that there is a semi-annual variation in magnetospheric flux circulation; however, it is not as large in amplitude as that in geomagnetic activity, consistent with the latter showing a non-linear (quadratic) variation with transpolar voltage. We find that during the persistent minimum of the UT variation in geomagnetic activity, between about 2 and 10 UT, there is also a persistent decrease in observed transpolar voltage, which may be, in part, caused by a decrease in reconnection voltage in the nightside cross-tail current sheet. We study the response of geomagnetic activity to estimated power input into the magnetosphere using interplanetary data from 1995 onwards, an interval for which the data are relatively free of data gaps. We find no consistent variation in the response delay with time-of-year F and, using the optimum lag, we show that the patterns of variation in F-year spectrograms are very similar for geomagnetic activity and power input into the magnetosphere, both for average values and for the occurrence of large events. The Russell–McPherron (R–M) mechanism is shown to be the central driver of this behaviour. However, the (R–M) effect on power input into the magnetosphere is small and there is a non-linear amplification of the semi-annual variation in the geomagnetic response, such that a very small asymmetry in power input into the magnetosphere Pα between the “favourable” and “unfavourable” polarities of the IMF BY component generates a greatly amplified geomagnetic response. The analysis strongly indicates that this amplification is associated with solar wind dynamic pressure and its role in squeezing the near-Earth tail and so modulating the storage and release of energy extracted from the solar wind. In this paper, we show that the equinoctial pattern is found in the residuals of fits of Pα to the am index and that the amplitude of these equinoctial patterns in the am fit residuals increases linearly with solar wind dynamic pressure. Similarly, the UT variation in am is also found in these fit residuals and also increases in amplitude with solar wind dynamic pressure.
Routine Use of Swallowing Outcome Measures Following Head and Neck Cancer in a Multidisciplinary Clinic Setting
Authors: Zuydam Annette C. , Rogers Simon N. , Grayson Kate , Probert Clare F.
Published: June 2020

Introduction Chemoradiotherapy treatment for head and neck cancer (HNC) can have a major impact on swallowing function and health-related quality of life.

The use of outcome measures in early detection of patients with swallowing problems provides the opportunity for targeting speech and language therapy (SLT) interventions to aid adaption and promote better clinical outcomes.

Objective The purpose of the present study was to assess relationships between four outcomes measures over time, in a cohort of HNC patients, treated by (chemo-)radiotherapy.

Methods Data were collected at 3 months and 12 months, on 49 consecutive patients with primary squamous cell cancer of the oropharynx, nasopharynx or hypopharynx stage T1–4, N0–2b, M0 disease.

Results Out of 49 eligible patients, 45 completed assessment at 3 months and 20 at 12 months. The 3-month outcomes gave a strong indication of performance at 1 year. There were several strong correlations found between measures. The strongest was between the 3-month Performance Status Scale for Head and Neck Cancer (PSSHN) and the 12-month PSSHN (rs = 0.761, n = 17), the 12-month PSSHN and the 12-month Functional Oral Intake Scale (FOIS) (rs = 0.823, n = 20), and the 12-month University of Washington Head and Neck Quality of Life (UWQoL) swallow and the 12-month Water Swallow Test (WST) capacity (rs = 0.759, n = 17).

Conclusion The UW-QoL swallow item and WST are easy to incorporate into routine care and should be used as part of a standard assessment of swallow outcome. These measures can serve to help screen patients for dysfunction and focus allocation of resources for those who would benefit from more comprehensive assessment and intervention by SLT.
The Role of Imaging in the Preoperative Assessment of Patients with Nasal Obstruction and Septal Deviation—A Retrospective Cohort Study
Authors: Carmel-Neiderman Narin Nard , Safadi Ahmad , Wengier Anat , Ziv-Baran Tomer , Warshavsky Anton , Ringel Barak , Horowitz Gilad , Fliss Dan M. , Abergel Avraham
Published: June 2020

Introduction Isolated nasal obstruction (INO) is a common complaint of multiple etiology. The preoperative evaluation of patients presenting with nasal obstruction and deviated nasal septum (DNS) does not typically include imaging. The benefits of performing computed tomography (CT) in the preoperative setting are inconclusive.

Objective Assessing the contribution of preoperative CT to the surgical treatment of non-sinusitis patients presenting with INO and DNS.

Methods A retrospective cohort study on patients referred to surgery for nasal obstruction due to DNS or turbinate hypertrophy between 2006 and 2015. Data was retrieved from patients' medical charts. The CT scans and clinical data were reassessed by a second surgeon blinded to the patients' clinical course.

Results Seventy of the 843 patients (8.06%) who underwent endoscopic sinonasal procedures during the study period had presented with INO and met the inclusion criteria. Thirty-eight (55.88%) of them underwent CT scans during their preoperative assessment. Modification of the initial preoperative planning based on the radiological findings was required in 32 cases (84.2%). When reassessed by a second blinded surgeon, 58% of cases required surgical modification rather than classical submucosal resection of nasal septum and turbinate reduction (P = 0.048).

Conclusion Computed tomography was found beneficial in the preoperative planning for patients with INO. The original surgical plan based upon physical examination findings was modified based on radiological findings in 84.2% of the patients.
Exfoliated hexagonal BN as gate dielectric for InSb nanowire quantum dots with improved gate hysteresis and charge noise
Authors: Jekat Felix , Pestka Benjamin , Car Diana , Gazibegović Saša , Flöhr Kilian , Heedt Sebastian , Schubert Jürgen , Liebmann Marcus , Bakkers Erik P. A. M. , Schäpers Thomas , Morgenstern Markus
Published: June 2020

We characterize InSb quantum dots induced by bottom finger gates within a nanowire that is grown via the vapor–liquid–solid process. The gates are separated from the nanowire by an exfoliated 35 nm thin hexagonal BN flake. We probe the Coulomb diamonds of the gate-induced quantum dot exhibiting a charging energy of ∼2.5 meV and orbital excitation energies up to 0.3 meV. The gate hysteresis for sweeps covering 5 Coulomb diamonds reveals an energy hysteresis of only 60 μeV between upward and downward sweeps. Charge noise is studied via long-term measurements at the slope of a Coulomb peak revealing a potential fluctuation of ∼1 μeV/Hz at 1 Hz. This makes h-BN a dielectric with the currently lowest gate hysteresis and lowest low-frequency potential fluctuations reported for low-gap III–V nanowires. The extracted values are similar to state-of-the-art quantum dots within Si/SiGe and Si/SiO2 systems.
First characterization of a superconducting filter-bank spectrometer for hyper-spectral microwave atmospheric sounding with transition edge sensor readout
Authors: Goldie D. J. , Thomas C. N. , Withington S. , Orlando A. , Sudiwala R. , Hargrave P. , Dongre P. K.
Published: June 2020

We describe the design, fabrication, integration, and characterization of a prototype superconducting filter bank with transition edge sensor readout designed to explore millimeter-wave detection at frequencies in the range of 40–65GHz. Results indicate highly uniform filter channel placement in frequency and high overall detection efficiency. The route to a full atmospheric sounding instrument in this frequency range is discussed.
Enhanced proton acceleration using hollow silica nano-sphere coated targets
Authors: Kumar Rakesh Y. , Singh Baljeet , Kundu M. , Rastogi Pankaj Kumar , Tata Sheroy , Rakesh Kumar V. , Lad Amit D. , Ved Yesh M. , Gopal R. , Sharma V. , Krishnamurthy M.
Published: June 2020

Acceleration of protons by transient strong electric fields formed with intense ultrashort laser pulses is important for advancements in radiography and biomedical applications. Controlling the absorption mechanisms by material modification or adding structural features to the solid substrate is important to enhance ion energies for a given laser intensity. We present here an experimental demonstration of enhanced proton acceleration when a BK-7 glass target is coated with 150 nm diameter silica hollow spheres. The hollow particle coated target yielded a maximum proton energy of ≥ 800 keV at a peak intensity of 1018 W cm−2 while the maximum energy is only up to 200 keV with a plain glass target under otherwise identical conditions. Two-dimensional particle in cell simulations demonstrate the role of local fields in the hollow spherical cavities that lead to the enhanced proton energies comparable to the experiments.
Simplified formulas for the generation of terahertz waves from semiconductor surfaces excited with a femtosecond laser
Authors: Tonouchi Masayoshi
Published: June 2020

We derive simple formulas to explain terahertz (THz) emission from semiconductor surfaces excited by a femtosecond (fs) laser. Femtosecond optical pulses with energies larger than the bandgap create photocarriers that travel and generate THz radiation, according to the time derivative of the photocurrent. By assuming that only electrons traveling in an ultrafast time scale, less than a few hundred fs, contribute to THz radiation, one can obtain simple expressions for the emission originating from the photocarrier drift accelerated with a built-in field or from the photocarrier diffusion. The emission amplitude of the former is in proportion with the electron mobility, the Schottky-barrier height, and the laser intensity and one of the latter with the laser intensity and diffusion coefficient squared. We also discuss the formula for emission from metal–insulator–semiconductor structures. The derived expressions are useful in understanding the THz emission properties observed by a laser THz emission microscope (LTEM), bringing the LTEM into real applications in the field of semiconductor research and development.
Delayed optical nutation inside a hollow-core photonic crystal fiber filled with acetylene
Authors: Ocegueda Manuel , Stepanov Serguei , Díaz Jordan I. , Casillas Nayeli , Hernández Eliseo , Iglesias Priscilla
Published: June 2020

The delayed optical nutation effect has been used to evaluate the longitudinal relaxation time (T1) inside an acetylene-filled hollow-core photonic crystal fiber (HC-PCF) at room temperature. In this experiment, sequences of two short optical pulses of 30 ns and 15 ns in width, respectively, with the maximum peak power up to ∼2.5 W, were generated at a laser wavelength of 1530.37 nm, which corresponds to the acetylene ro-vibrational P9 absorption line. The gas pressure inside the 1 m-long HC-PCF varied in the range 0.1–1 Torr. Numerical simulations based on the optical Bloch equations allowed us to evaluate the longitudinal relaxation time as T1∼9ns, proving to be fundamentally limited by the transit-time broadening. Also, the obtained results revealed the influence of slow and fast molecules in the form of a non-exponential decay of the delayed-nutation signals.
Water condensate morphologies on a cantilevered microfiber
Authors: Zhu Fangqi , Fang Wen-Zhen , Zhang Hui , Zhu Zhibing , New Tze How , Zhao Yugang , Yang Chun
Published: June 2020

Water collection via fiber-based coalescers shows promise in mitigating increasing water scarcity, and most studies usually focus on the water collection by accumulating water through successive coalescences of fog in the absence of condensation. Here, we report on non-uniform condensate morphologies observed during air–vapor mixture condensation on a cantilevered microfiber. Due to the competition between thermal conduction resistance within the fiber and condensation heat transfer resistance on the fiber surface, the vapor diffusive flux along the fiber varies accordingly, engendering three representative condensate morphologies. We systematically examine the effects of fiber length, diameter, and material (constantan, 316L steel, and alumel) on these condensate morphologies. Scaling analyses are also provided to reveal the underlying physics. Our experimental investigations and theoretical analyses reported in this work shed more light on air–vapor mixture condensation mechanisms that could pave the way to future condensation-associated applications.
Solute strongly impacts freezing under confinement
Authors: Ginot Félix , Lenavetier Théo , Dedovets Dmytro , Deville Sylvain
Published: June 2020

The presence of liquid water in frozen media impacts the strength of soils, the growth of frost heave, plant life and microbial activities, or the durability of infrastructures in cold regions. If the effect of confinement alone on freezing is well known, water is never pure and solutes depressing the freezing point are naturally found. However, the combination of confinement and solute is poorly understood. Here, we study in situ the freezing of water in a model porous medium made of densely packed particles with various salt (KCl) concentrations. We demonstrate a synergistic effect of solute with confinement: the freezing front, initially heterogeneous due to confinement, drives solute enrichment in the remaining liquid, further depressing its freezing point. This increases the local freezing point depression and results in much larger mushy layers where ice and liquid water coexist. We compare our experimental freezing profile with theory and estimate the local solute concentration to increase by more than one order of magnitude through the freezing process. These results imply that even low solute concentrations may have important effects on the distribution of water in frozen porous media and should help explain the variety of freezing patterns observed experimentally. This may be critical for cryo-tolerance of construction materials and organisms and will help understanding solute precipitation and redistribution in soils.
High quality epitaxial Mn2Au (001) thin films grown by molecular beam epitaxy
Authors: Bommanaboyena S. P. , Bergfeldt T. , Heller R. , Kläui M. , Jourdan M.
Published: June 2020

The recently discovered phenomenon of Néel spin–orbit torque in antiferromagnetic Mn2Au [Bodnar et al., Nat. Commun. 9, 348 (2018); Meinert et al., Phys. Rev. Appl. 9, 064040 (2018); Bodnar et al., Phys. Rev. B 99, 140409(R) (2019)] has generated huge interest in this material for spintronics applications. In this paper, we report the preparation and characterization of high quality Mn2Au thin films by molecular beam epitaxy and compare them with magnetron sputtered samples. The films were characterized for their structural and morphological properties using reflective high-energy electron diffraction, x-ray diffraction, x-ray reflectometry, atomic force microscopy, and temperature dependent resistance measurements. The thin film composition was determined using both inductively coupled plasma optical emission spectroscopy and Rutherford backscattering spectrometry techniques. The MBE-grown films were found to show a superior smooth morphology and a low defect concentration, resulting in reduced scattering of the charge carriers.
An analysis of carrier dynamics in methylammonium lead triiodide perovskite solar cells using cross correlation noise spectroscopy
Authors: Davenport Kevin , Zhang Fei , Hayward Mark , Draper Logan , Zhu Kai , Rogachev Andrey
Published: June 2020

Using cross correlation current noise spectroscopy, we have investigated carrier dynamics in methylammonium lead triiodide solar cells. This method provides space selectivity for devices with a planar multi-layered structure, effectively amplifying current noise contributions coming from the most resistive element of the stack. In the studied solar cells, we observe near full-scale shot noise, indicating the dominance of noise generation by a single source, likely the interface between the perovskite and the spiro-organic 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9′-spirobifluorene hole-transport layer. We argue that the strong 1/f noise term has contributions from both the perovskite layer and interfaces. It displays a non-ideal dependence on photocurrent, S∝I1.4 (instead of usual S∝I2), which is likely due to current-induced halide migration. Finally, we observe generation–recombination noise. We argue that this contribution is due to bimolecular recombination in the perovskite bulk absorption layer. Extrapolating our results, we estimate that at standard 1 sun illumination, the electron–hole recombination time is 5 μs.
Tracking nanoparticle growth in pulsed carbon arc discharge
Authors: Corbella Carles , Portal Sabine , Rao Jiancun , Kundrapu Madhusudhan N. , Keidar Michael
Published: June 2020

The dynamics of nanoparticle growth in pulsed anodic arc discharge has been studied in time-resolved mode. To this end, a fast moving probe was employed to extract the material generated in a pulsed arc plasma held between two graphite electrodes. The probe motion was synchronized with the pulse phase and the exposure time to the plasma was set to 10 ms. The graphite anode was eroded in a helium atmosphere (300 Torr) by an arc plasma pulsed at 1 Hz with a 10% duty cycle and showing 250 A of peak current. The structure and morphology of the probe depositions were characterized by Raman spectroscopy, scanning electron microscopy, and focused ion beam. A maximal deposition rate of 260 μm/s was measured 5 mm away from the arc core during the active 0.1 s of the pulse. Such a rate yields a growth flux of 1.3 × 1021 cm−2 s−1, rich in carbon nanostructures (graphene platelets, nanotubes) with a characteristic aggregate size within 1–10 μm. The deposition during the inactive 0.9 s of the pulse was several orders of magnitude slower and consisted of amorphous carbon traces. Moreover, the nanoparticle distribution along the collecting probe is correlated with the pulse phase, thereby providing information on particle transport. Pulsed nanosynthesis can be modeled as a periodical growth process, where the volume and propagation velocity of the growth region can be adjusted through modulation of the pulse signal waveform. The proposed model constitutes a suitable framework to investigate the pulsed arc synthesis of nanomaterials with tailored physical and chemical properties.
Experimental study of substrate roughness on the local glass transition of polystyrene
Authors: Huang Xinru , Thees Michael F. , Size William B. , Roth Connie B.
Published: June 2020

Numerous computer simulations have shown that local dynamics associated with the glass transition can be slower next to rough interfaces compared with smooth interfaces. Even though the impact of surface roughness has been frequently considered computationally and theoretically, almost no experimental studies exist investigating these effects. Using a hydrogen fluoride vapor treatment, we created silica substrates with an increase in roughness that left the surface chemistry unchanged. The local glass transition temperature Tg near silica substrates with an increase in roughness was measured using fluorescence, finding an increase in local Tg of 10 K with an increase in the root-mean-square roughness Rrms from 0.5 nm to 11 nm. Characterization of the substrate roughness needed to create an experimental change in local Tg was found to be quite large, leaving the mechanism for this observed behavior uncertain. We discuss possible causes associated with polymer chains being more readily able to make surface contacts and adsorb to roughened interfaces.
Elastocaloric effect in vanadium (IV) oxide
Authors: Ouyang Gaoyuan , Pan Chaochao , Wolf Sam , Mohapatra Pratyasha , Takeuchi Ichiro , Cui Jun
Published: June 2020

Elastocaloric cooling utilizes the latent heat associated with stress-induced reversible phase transformations to achieve cooling. Currently, the key barrier to this technology is its prohibitive cost due to the high elastocaloric material cost and the large stress required to drive the cooling cycle. Vanadium (IV) oxide (VO2) is a good candidate, and it is relatively cheap. Our calorimetry study shows it exhibits a reversible phase transformation with a large latent heat of 31.5 J/g as well as excellent functional stability. Its transformation temperature and latent heat are tunable via heat treatment. We demonstrate that VO2 powders can be cyclically compressed in a steel tube using a steel plunger to drive the elastocaloric effect. The application of relatively low stress of 300 MPa is sufficient to result in a reversible temperature change of 0.5 °C on the powder compact. Further improvement of reversible temperature change to 1.6 °C under 300 MPa is achieved by adding conductive copper powders. Future efforts should focus on improving material properties such as heat capacity and thermal conductivity for candidate ceramic oxides to maximize elastocaloric effects.
On the use of DFT+U to describe the electronic structure of TiO2 nanoparticles: (TiO2)35 as a case study
Authors: Morales-García Ángel , Rhatigan Stephen , Nolan Michael , Illas Francesc
Published: June 2020

One of the main drawbacks in the density functional theory (DFT) formalism is the underestimation of the energy gaps in semiconducting materials. The combination of DFT with an explicit treatment of the electronic correlation with a Hubbard-like model, known as the DFT+U method, has been extensively applied to open up the energy gap in materials. Here, we introduce a systematic study where the selection of the U parameter is analyzed considering two different basis sets: plane-waves and numerical atomic orbitals (NAOs), together with different implementations for including U, to investigate the structural and electronic properties of a well-defined bipyramidal (TiO2)35 nanoparticle. This study reveals, as expected, that a certain U value can reproduce the experimental value for the energy gap. However, there is a high dependence on the choice of basis set and on the U parameter employed. The present study shows that the linear combination of the NAO basis functions, as implemented in Fritz Haber Institute ab initio molecular simulation (FHI-aims), requires, requires a lower U value than the simplified rotationally invariant approach, as implemented in the Vienna ab initio simulation package (VASP). Therefore, the transfer of U values between codes is unfeasible and not recommended, demanding initial benchmark studies for the property of interest as a reference to determine the appropriate value of U.