bluuebunny/crossref_metadata_2025 huggingface dataset:
CHARACTERIZATION OF PROPERTIES OF PVDF/POLY(DIMETHYLSILOXANE) COMPOSITES SEPARATOR WITH BLENDING MEMBRANE METHOD
Authors: Arifin Devi Eka Septiyani
Published: July 2019

The aims of this research to make poly(vinylidene fluoride) (PVDF) and poly(dimetilsiloksan) (PDMS) composites separator with blending membrane method. Synthesized of  PVDF/PDMS composites separator used various ratio were 10/0, 9/1, 8/2, and 7/3. The purpose of increasing concentration of PDMS/PVDF to improve the performance of the composites separator which includes a dimensions of porosity, a pore density, and a electrical conductivity. Based on crystallographic analysis using XRD, the increasing concentration number of PDMS to make compositess was influence decreasing of crystallinity until 29.26% in a ratio 7/3.The analysing of FTIR have sound the wavenumber of each phase can distinguish, which this material includes in the criteria of the composites. The result using XRD and FTIR to material PVDF/PDMS composites in all of the ratio constituens have shown the identification of the structure α-phase of PVDF. The increase of concentration number PDMS influenced decreasing of pore dimension and increasing of pore density with the small of pore dimension 1.71 µm and pore density 4.07x1011 count/m2 inthe ratio 7/3. In a ratio 7/3, the value of the electrical conductivity was 3.45x10-4S/cm and the resistance increased up to 80%.
Analisis Efektivitas Biji dan Daun Kelor (Moringa oleifera) Untuk Penjernihan Air
Authors: Ariyatun Ariyatun , Ningrum Puji , Musyarofah Musyarofah , Inayah Nurul
Published: July 2019

Penelitian ini untuk menganalisis keefektifan bahan dari biji dan daun kelor (Moringa oleifera) yang digunakan sebagai koagulan.  Pada penelitian ini mengambil sampel satu liter air sungai yang keruh untuk setiap percobaan. Sebelumnya air diukur dahulu dengan turbidimeter. Berdasarkan hasil penelitian penjernihan Air sungai dengan bubuk biji kelor didapatkan hasil 8,67 NTU untuk bubuk biji kelor 0.5 gram , 4.29 NTU untuk biji kelor 0.2 gram dan 3.07 NTU dengan biji kelor 0.1 gram. Hal ini artinya dalam praktikum penjernihan air dengan bubuk biji kelor yang telah dilakukan kualitas air bertambah jernih dan masih memenuhi persyaratan air bersih yang diperbolehkan. Dapat disimpulkan pula bahwa dalam penjernihan air 1 liter lebih efektif / idealnya dengan 0.1 gram bubuk biji kelor.
Ag-ZSM-11 Zeolite Synthesis Using Silica from Elephant Grass for LED Application
Authors: Sundari Citra D. D. , Setiadji Soni , Firmansyah Atthar Luqman , Abdurahman Dede , Nurbaeti Denia Febby
Published: July 2019

Silica (SiO2) has been successfully isolated from elephant grass by the sol gel method through pH regulation using NaOH and HCl. The resulting silica has an amorphous character with crystalline phase impurities. The isolated silica was then used as a source of silica for the synthesis of ZSM-11 zeolite using the hydrothermal method with a ratio of SiO2 : TBAOH : H2O = 1 : 0.35 : 25. XRD characterization results confirmed the formation of ZSM-11 zeolite. The SEM results show that the ZSM-11 zeolite crystal morphology is oval with crystal growth in all directions. Immersion of the synthesized ZSM-11 zeolite into AgNO3 solution and followed by calcination resulted in zeolite Ag-ZSM-11 which has different optical properties compared to the initial ZSM-11 zeolite. Zeolite ZSM-11 gives purple luminescence while zeolite Ag-ZSM-11 gives pink luminescence when illuminated under UV lights
Water–energy nexus of the Eastern Route of China's South-to-North Water Transfer Project
Authors: Chen Dan , Zhang Di , Luo Zhaohui , Webber Michael , Rogers Sarah
Published: July 2019

This article investigates the energy intensity and related impacts of the Eastern Route of China's South-North Water Transfer Project, based on the concept of the water–energy nexus. It finds that from November 2013 to May 2017 a total of 2.35 billion kWh of energy was consumed to transfer 15.5 billion m3 water driven by a large-scale system of pumping stations. This energy production required 7.4 million m3 of virtual water and emitted 1.93 MtCO2e of carbon. An average water–energy nexus ratio of 0.05% indicates that transferring 100 m3 of water consumes 0.05 m3 of virtual water due to the electricity consumption of the Eastern Route's pumping stations. It is estimated that to transfer 7.3 billion m3 water by 2030, this mega project will consume 1.35 billion kWh of energy, 4.6 million m3 of virtual water and emit 0.94 MtCO2e of carbon. These findings and scenario analysis demonstrate that strategies are needed for mitigating the energy intensity of the Eastern Route, such as improved pumping efficiency, reduced water loss during water delivery, decreased water quotas, and promotion of other, less carbon-intensive water sources in destination provinces.
Defluoridation of calcium-rich groundwater using iron oxide nanoparticles
Authors: Sudasinghe Madhusha , Jayaweera Mahesh , Gunawardana Buddhika , Manatunge Jagath , Madhusanka Gayan
Published: July 2019

It has been suggested that moderate to high fluoride ion concentrations in the presence of calcium in groundwater can represent human health hazards resulting in possible lesions in tubular cells, leading to chronic kidney disease of unknown etiology (CKDu). This study focuses on fluoride removal in the presence of calcium using iron oxide nanoparticles (FeONs) as an effective adsorbent in single- and multi-solute batch-studies. Fluoride and calcium removal by FeONs in single-solute batch-studies occurred only by adsorption. Both species followed the Langmuir isotherm model and pseudo second-order kinetics, indicating monolayer adsorption and chemisorption, respectively. In multi-solute batch-studies, fluoride removal was attributed to adsorption and chemical precipitation forming CaF2 in almost similar magnitude. For calcium removal in multi-solute studies, adsorption, co-precipitation, and precipitation were the prominent mechanisms, with co-precipitation dominant. Thus, FeONs are effective in fluoride removal by adsorption in both the presence and absence of calcium. FeONs could also be used successfully year-round in tropical climates, where calcium levels vary substantially, to lessen the risk of CKDu.
Microbial wash water quality on dairy farms from Galicia (NW Spain)
Authors: Saavedra F. J. , Yus E. , Diéguez F. J.
Published: July 2019

This study evaluated the microbiological quality of wash water used in dairy farms from Galicia (NW Spain) based on the total coliform, faecal coliform and faecal streptococci counts. The paper aimed to identify geographical areas that are at a high risk for bacterial contamination of wash water and to study the temporal distribution of positive samples. Water samples from 120 farms, whose water supply came from a private well, were tested for the presence of the three mentioned bacterial groups by the membrane filtration method. To investigate whether the presence of positive herds for a particular bacterial group in water samples was higher in some areas or during a specific time period, data were tested using the Bernoulli model. In farms without a purification system, the prevalence of positive samples for total coliform, faecal coliform and faecal streptococci was 36.7%, 13.3% and 24.5%, respectively. In farms using hydrogen peroxide, these figures were 15.4%, 7.7% and 7.7%, respectively. In farms using chlorine or ultraviolet radiation all the samples were negative for the three bacterial groups. The spatial analysis identified one statistically significant spatial cluster of herds with positive samples of faecal streptococci in an area characterized by a high cattle density. Moreover, one most likely temporal cluster was identified for each of the three groups between July and August 2017, which were the driest months in the studied area.
Qualificação profissional de camareiras de hotéis e a crítica que Paulo Freire não escreveu
Authors: De Paula Angela Teberga , Herédia Vania Beatriz Merlotti
Published: July 2019

Apesar da enorme importância do ofício das camareiras para o bom funcionamento dos hotéis, cursos de qualificação dessa ocupação tendem a atender as necessidades mais imediatas do mercado hoteleiro. Nesse contexto, o objetivo principal deste trabalho é problematizar a qualificação profissional de camareiras de hotéis a partir dos estudos de Paulo Freire. Apesar de não haver uma crítica sistemática de Paulo Freire à educação profissional, pode-se inferir como a crítica freiriana ao ensino chegaria aos cursos de qualificação profissional. A qualificação das camareiras ocorre em nível de qualificação profissional, em que a escolaridade básica exigida é o ensino fundamental, habilitando os alunos ao uso de equipamentos e materiais adequados, e à manutenção e limpeza dos apartamentos. Em nosso entendimento, o ensino profissional tem um papel de suma importância para a formação humanista das trabalhadoras, devendo, por isso, respeitar o “saber de experiência feito” das educandas-trabalhadoras, ter o trabalho como princípio educativo e ser crítica à reprodução do capital – alicerces da teoria Freiriana. Constitui-se uma pesquisa exploratória de revisão teórica (pesquisas bibliográfica e documental) e utiliza-se como pesquisa empírica a cidade de Brasília (Distrito Federal) para o estudo do perfil das camareiras de hotéis e da oferta de cursos de qualificação profissional do segmento.
Comer à luz dos fogos de artifício: Um evento gastronômico impulsionado pela crise econômica catalã
Authors: Luderer Cynthia Arantes
Published: July 2019

Os eventos gastronômicos têm se destacado na contemporaneidade e são passíveis de contribuir em vários cenários, quer quando estão relacionados aos aspectos sociais, econômicos ou culturais. Nesse sentido, o propósito deste estudo de caso foi conferir: qual o papel de um evento gastronômico quando se vive um período de crise econômica? Para tanto, o objeto selecionado para este trabalho foi um evento gastronômico criado por chefs de cozinha de Tarragona, uma cidade turística catalã. Com base nesse suporte, foi analisada a dinâmica comunicacional empregada pelos agentes envolvidos no processo de criação e organização desse evento, criado em 2010, que passou a fazer parte do cronograma turístico dessa cidade. Com cunho exploratório e qualitativo, esta pesquisa, desenvolvida em campo, apoiou-se nos princípios da Semiótica e da Análise do Discurso para examinar as narrativas dos agentes entrevistados, assim como os textos virtuais dedicados a divulgar o evento em pauta. Além de destacar o turismo da cidade, este estudo conclui que, em tempos de crise econômica, os eventos gastronômicos são apresentados como um dispositivo para estimular os agentes políticos e os gastronômicos a se unirem, como também criam uma oportunidade para os cidadãos-consumidores desfrutarem de seu tempo de ócio, num período no qual eles são limitados por questões econômicas.
Withdrawn: Association between Alzheimer's Disease and Cancer - A Short Overview
Authors: Szczechowiak Katarzyna , Brzecka Anna , Hachiya Naomi , Wyka Joanna , Leszek Jerzy
Published: July 2019

The following article has been withdrawn at the request of the authors and editor of the journal Current Medicinal Chemistry:

Title: Association between Alzheimer's Disease and Cancer - A Short Overview.

Authors: Katarzyna Szczechowiak, Anna Brzecka, Naomi Hachiya, Joanna Wyka and Jerzy Leszek*

Bentham Science apologizes to the readers of the journal for any inconvenience this may cause.

Bentham Science Disclaimer: It is a condition of publication that manuscripts submitted to this journal have not been published and will not be
simultaneously submitted or published elsewhere. Furthermore, any data, illustration, structure or table that has
been published elsewhere must be reported, and copyright permission for reproduction must be obtained. Plagiarism
is strictly forbidden, and by submitting the article for publication the authors agree that the publishers have the legal
right to take appropriate action against the authors, if plagiarism or fabricated information is discovered. By submitting
a manuscript the authors agree that the copyright of their article is transferred to the publishers if and when the
article is accepted for publication.
Diet and Nutritional Interventions with the Special Role of Myo-Inositol in Gestational Diabetes Mellitus Management. An Evidence-Based Critical Appraisal
Authors: Reyes-Muñoz Enrique , Guardo Federica Di , Ciebiera Michal , Kahramanoglu Ilker , Sathyapalan Thozhukat , Lin Li-Te , Shah Mohsin , Karaman Erbil , Fan Shangrong , Zito Gabriella , Noventa Marco
Published: July 2019

Background:

Gestational Diabetes Mellitus (GDM), defined as glucose intolerance with onset or first
recognition during pregnancy, represents one of the most common maternal-fetal complications during pregnancy
and it is associated with poor perinatal outcomes. To date, GDM is a rising condition over the last decades coinciding
with the ongoing epidemic of obesity and Type 2 Diabetes Mellitus (T2DM).

Objective:

The aim of this review is to discuss the role of diet and nutritional interventions in preventing GDM
with the explanation of the special role of myo-inositol (MI) in this matter.

Methods:

We performed an overview of the most recent literature data on the subject with particular attention to
the effectiveness of diet and nutritional interventions in the prevention of GDM with the special role of MI.

Results:

Nutritional intervention and physical activity before and during pregnancy are mandatory in women
affected by GDM. Moreover, the availability of insulin-sensitizers such as different forms of inositol has dramatically
changed the scenario, allowing the treatment of several metabolic diseases, such as those related to glucose
dysbalance. Although the optimal dose, frequency, and form of MI administration need to be further investigated,
diet supplementation with MI appears to be an attractive alternative for the GDM prevention as well as for the
reduction of GDM-related complications.

Conclusion:

More studies should be conducted to prove the most effective nutritional intervention in GDM.
Regarding the potential effectiveness of MI, further evidence in multicenter, randomized controlled trials is
needed to draw firm conclusions.
A Brief Review of the Computational Identification of Antifreeze Protein
Authors: Wang Fang , Guan Zheng-Xing , Dao Fu-Ying , Ding Hui
Published: July 2019

Lots of cold-adapted organisms could produce antifreeze proteins (AFPs) to counter the freezing of cell fluids by controlling the growth of ice crystal. AFPs have been found in various species such as in vertebrates, invertebrates, plants, bacteria, and fungi. These AFPs from fish, insects and plants displayed a high diversity. Thus, the identification of the AFPs is a challenging task in computational proteomics. With the accumulation of AFPs and development of machine meaning methods, it is possible to construct a high-throughput tool to timely identify the AFPs. In this review, we briefly reviewed the application of machine learning methods in antifreeze proteins identification from difference section, including published benchmark dataset, sequence descriptor, classification algorithms and published methods. We hope that this review will produce new ideas and directions for the researches in identifying antifreeze proteins.
Computational and Experimental Approaches to Design Inhibitors of Amylin Aggregation
Authors: Kumar Ammu Prasanna , Lee Sungmun , Lukman Suryani
Published: July 2019

Amylin is a neuroendocrine peptide hormone secreted by pancreatic ß-cells; however,
amylin is toxic to ß-cells when it is aggregated in type 2 diabetes mellitus (T2DM). It is important to
understand amylin’s structures and aggregation mechanism for the discovery and design of effective
drugs to inhibit amylin aggregation. In this review, we investigated experimental and computational
studies on amylin structures and inhibitors. Our review provides some novel insights into amylin, particularly
for the design of its aggregation inhibitors to treat T2DM. We detailed the potential inhibitors
that have been studied hitherto and highlighted the neglected need to consider different amylin attributes
that depend on the presence/absence of physiologically relevant conditions, such as membranes.
These conditions and the experimental methods can greatly influence the results of studies on amylininhibitor
complexes. Text-mining over 3,000 amylin-related PubMed abstracts suggests the combined
therapeutic potential of amylin with leptin and glucagon-like peptide-1, which are two key hormones
in obesity. The results also suggest that targeting amylin aggregation can contribute to therapeutic efforts
for Alzheimer’s disease (AD). Therefore, we have also reviewed the role of amylin in other conditions
including obesity and AD. Finally, we provided insights for designing inhibitors of different
types (small molecules, proteins, peptides/mimetics, metal ions) to inhibit amylin aggregation.
Design, Synthesis and Molluscicidal Activity of New Phosphorus Compounds Bearing Fluorine Substituted 1,2,4-Triazolo[3,2-c][1,2,4]triazine Derivatives
Authors: Abdel-Rahman Reda M. , Alharbi Abdulrahman S. , Alshammari Nawaa A. , Adnan Yousuf O.
Published: July 2019

Novel phosphorus compounds bearing fluorine substituted 1,2,4-triazolo[3,2-c][1,2,4]triazine derivatives have been synthesized, starting from ring closure reactions of 3-hydrazino-4-(4`- fluorophenyl)-5-(prydin-4`-yl)-1,2,4-trizole (4) with 1,2-bioxygen compounds followed by the treatment with functional phosphorus compounds. The new systems obtained were evaluated as molluscicidal targets against some snails. Structures of these targets were elucidated upon their elemental and spectral data.
New Derivatization Methodology of 4-aminobenzoic Acid from its Dietary Supplements: Kinetic Spectrophotometric Methods for Determination
Authors: Naser Naser A. , Alasedi Kasim M. , Khan Zainab A.
Published: July 2019

Background:

A new approach describing the validation and development of an easy, new spectrophotometric and kinetic method for identification of para-aminobenzoic acid in dietary supplement has been performed. In this study, para-aminobenzoic acid was derived in a pH-controlled environment, as a new organic compound 4(4-Benzophenylazo)pyrogallol, by incorporating diazotized para-aminobenzoic acid with pyrogallol.

Objective:

The determination of para-aminobenzoic acid was conducted by the fixed time and initial rate techniques. These approaches were based on the reaction of the compound containing paraaminobenzoic acid, 4(4-Benzophenylazo)pyrogallol, with Ag(I) to form colored product with a maximum absorbance at 468nm. Both of these techniques were adopted for constructing the calibration curves and examined for their suitability for the quantitation of para-aminobenzoic acid in dietary supplement.

Methods:

The determination process was established, using initial rate and fixed time kinetic spectrophotometric methods.

Results:

4(4-Benzophenylazo)pyrogallol was characterized using proton-nuclear magnetic resonance, Fourier-transform infrared, differential scanning calorimetry and thermogravimetric thermal methods, gas chromatography–mass techniques, and solvatochromic behavior in solvents with different polarities was also examined.

Conclusion:

For the first time, para-aminobenzoic acid was well determined by incorporating it as an organic solid compound, 4(4-Benzophenylazo)pyrogallol, through coupling pyrogallol with diazotized para-aminobenzoic acid in regulated pH medium, ranging between 5.0 to 6.0. The existence of common excipients in the dietary supplement did not produce any significant interference. F- and ttest data analysis were used for statistical comparison of the suggested techniques with that of reference method, demonstrating excellent agreement with no significant difference in the associated precision and accuracy.
In Silico Design of a Single Protein Molecular Photoreaction Center
Authors: Mishra Nibedita , Mohapatra Pranab K. , Raval Mukesh K.
Published: July 2019

Background:

Research on harvesting solar energy through an artificial photosynthetic device
is gaining momentum in the present era. The device is a promising solution to the energy crisis by
overcoming the crunch in fossil fuel and low efficiency of heat engine. Reports are available on design
of isolated parts of the photosynthetic device, for example, only sensitizer or only redox unit containing
metallo-peptides.

Objective:

An attempt has been made to design an in silico photoreaction center in a single chain protein
matrix containing all the three basic units: sensitizer, electron donor, and acceptor mimicking the
photosynthetic reaction center II.

Methods:

A single chain of a protein containing a closely packed transmembrane four-helix bundle (PDB
ID 2bl2 A) is selected for the purpose. The protein is suitably mutated in silico to accommodate the basic
elements of a reaction center: Mn-Ca binding site as water oxidizing moiety, Fe-binding site as quinine
reducing moiety, and MgDPP as photosensitizer to achieve the desired function of photoredox reaction.

Results:

A photoelectron transport protein has been designed, which may incorporate into the bilayer
membrane system. It has the potential to photo-oxidize water to oxygen on one side and reduce quinone
on the other side of the membrane. The stability and transmembrane orientation of the molecular
device in an artificial membrane system has been validated theoretically by molecular dynamics study.

Conclusion:

An attempt to incorporate in silico all the elements essential for a photoelectron transport
device into a single chain transmembrane protein model is the first of its kind. Donor and acceptor
moieties are separated on the inner and outer side of a membrane bilayer. These features make the
model unique and novel. The design of the model is the first step towards the study of experimental
viability of the model, which remains to be validated in future.
Диффузия и взаимодействие In и As, имплантированных в пленки SiO-=SUB=-2-=/SUB=-
Authors: Тысченко И.Е. , Voelskow M. , Михайлов А.Н. , Тетельбаум Д.И.
Published: July 2019

AbstractBy means of Rutherford backscattering spectrometry, electron microscopy, and energy-dispersive X-ray spectroscopy, the distribution and interaction of In and As atoms implanted into thermally grown SiO_2 films to concentrations of about 1.5 at % are studied in relation to the temperature of subsequent annealing in nitrogen vapors in the range of T = 800–1100°C. It is found that annealing at T = 800–900°C results in the segregation of As atoms at a depth corresponding to the As^+-ion range and in the formation of As nanoclusters that serve as sinks for In atoms. An increase in the annealing temperature to 1100°C yields the segregation of In atoms at the surface of SiO_2 with the simultaneous enhanced diffusion of As atoms. The corresponding diffusion coefficient is D _As = 3.2 × 10^–14 cm^2 s^–1.
Наблюдение областей отрицательной дифференциальной проводимости и генерации тока при туннелировании через нульмерные уровни дефектов барьера h-BN в гетероструктурах графен/h-BN/графен
Authors: Ханин Ю.Н. , Вдовин Е.Е. , Мищенко А. , Новоселов К.С.
Published: July 2019

AbstractTunneling and magnetic tunneling are investigated in graphene/ h -BN/graphene van der Waals heterosystems. Two new types of systems are found, in which negative differential conductivity regions are implemented due to resonant tunneling through defect levels in the h -BN barrier, and current caused by their presence is generated.
К теории плазмон-экситонов: оценка константы взаимодействия и оптический спектр
Authors: Аверкиев Н.С. , Коротченков А.В. , Кособукин В.А.
Published: July 2019

AbstractThe structure of the optical spectra related to the resonant interaction of quasi-two-dimensional excitons and localized plasmons is investigated theoretically. The constant of plasmon–exciton coupling is estimated in a model considering a semiconductor quantum well close to a layer of metal nanoparticles in an adjacent dielectric medium. Numerical calculations carried out for GaAs/Ag and ZnO/Al nanosystems indicate that near the plasmon–exciton resonance the spectrum features a double-peak structure which exhibits the plasmon-excitonic anticrossing behavior upon detuning from exact resonance.
Синтез, фото- и катодолюминесцентные свойства коллоидных квантовых точек CdSe, CdTe, PbS, InSb, GaAs
Authors: Жуков Н.Д. , Крыльский Д.В. , Шишкин М.И. , Хазанов А.А.
Published: July 2019

AbstractQuantum dots of the group of wide-gap and narrow-gap semiconductors are synthesized and investigated under identical conditions, which makes it possible to perform the comparative analysis and modeling of the mechanisms of radiative recombination and luminescence, for which a stable exciton bond between the electron and hole has an important role. Exciton states are unstable for quantum dots without a shell and narrow-gap semiconductors, which leads to a substantial decrease in the probability of radiative recombination and, correspondingly, the quantum yield of luminescence. The experimental values of the spectral position of the luminescence maximum for quantum dots with clear manifestation of the exciton recombination mechanism noticeably shift to the long-wavelength region with respect to the calculated ones. In calculations and analysis, we use the effective electron mass for bulk semiconductors. The observed good correspondence of the calculated values of the maximum and spectral band with the experiment can mean that quantum dots have a long-range order crystalline structure similar to that one observed in single crystals and polycrystals.
Влияние висмута на свойства упругонапряженных гетероструктур AlGaInAsP/InP
Authors: Лунина М.Л. , Лунин Л.С. , Алфимова Д.Л. , Пащенко А.С. , Данилина Э.М. , Нефедов В.В.
Published: July 2019

AbstractThe results of growing elastically stressed AlGaInAsP〈Bi〉 thin epitaxial layers from the liquid phase on indium phosphide substrates in a temperature-gradient field are discussed. The effect of bismuth on the structural perfection, the luminescence properties, and the external quantum yield of AlGaInAsP〈Bi〉/InP heterostructures is investigated.
Релаксационные, термические и межфазные эффекты в композитах полимер-сегнетопьезокерамика различной структуры
Authors: Курбанов М.А. , Рамазанова И.С. , Дадашов З.А. , Мамедов Ф.И. , Гусейнова Г.Х. , Юсифова У.В. , Татардар Ф.Н. , Фараджзаде И.А.
Published: July 2019

AbstractThe relaxation and thermal processes and interphase phenomena in composites based on ferroelectrics and a polymer matrix are studied. It is shown that the charge stabilized at the interface of the composite during its electrothermopolarization is mainly determined by the structure of the polymer matrix and the piezoelectric phase. The results obtained make it possible to reveal the main factors affecting the piezoelectric properties of the heterogeneous polymer–ferroelectric ceramic system. Polyolefins and fluorine-containing polar polymers are used as the organic phase, and ferroelectric ceramics of rhombohedral, tetragonal, and mixed structures serve as the inorganic phase. The relaxation processes and interphase phenomena are studied using a differential scanning calorimeter, and the charge state is analyzed by recording the thermally stimulated depolarization current. The charge-state stability is determined by the electret potential difference of the composites. The molecular relaxation is analyzed by the dielectric method. It is established that the composites in which the interphase interaction is more pronounced are characterized by high piezoelectric properties.
Sensing amorphous/crystalline silicon surface passivation by attenuated total reflection infrared spectroscopy of amorphous silicon on glass -=SUP=-*-=/SUP=-
Authors: Abolmasov S.N. , Abramov A.S. , Semenov A.V. , Shakhray I.S. , Terukov E.I. , Malchukova E.V. , Trapeznikova I.N.
Published: July 2019

AbstractAttenuated total reflection Fourier transform infrared (ATR FTIR) spectroscopy and effective lifetime measurements have been used to characterize amorphous/crystalline silicon surface passivation in silicon heterojunction solar cells. The comparative studies show a strong link between microstructure factor R * and effective lifetime of amorphous silicon ( a -Si:H) passivation layers incorporating an interface buffer layer, which prevents the epitaxial growth. It is demonstrated that thin a -Si:H films deposited on glass can be used as ATR substrates in this case. The obtained results show that a -Si:H films with R * close to 0.1 are required for manufacturing of high-efficiency (>23%) silicon heterojunction solar cells.
Структурные и морфологичеcкие свойства гибридных гетероструктур на основе GaN, выращенного на "податливой" подложке por-Si(111)
Authors: Середин П.В. , Голощапов Д.Л. , Золотухин Д.С. , Леньшин А.С. , Мизеров А.М. , Арсентьев И.Н. , Leiste Harald , Rinke Monika
Published: July 2019

AbstractThe possibility of synthesizing integrated GaN/por-Si heterostructures by plasma-assisted molecular beam epitaxy without an A1N/Si buffer layer is demonstrated. The beneficial effect of the high-temperature nitridation of a silicon substrate before GaN growth on the crystal quality of the GaN/Si layers is shown. It is established that, to obtain two-dimensional GaN layers on Si(111), it is reasonable to use compliant por-Si substrates and low-temperature GaN seed layers with a 3D morphology synthesized by plasma-assisted molecular beam epitaxy at relatively low substrate temperatures under stoichiometric conditions and upon enrichment with nitrogen. In this case, a self-assembled array of GaN seed nanocolumns with a fairly uniform diameter distribution forms on the por-Si substrate surface. The basic GaN layers, in turn, should be grown at a high temperature under stoichiometric conditions upon enrichment with gallium, upon which the coalescence of nucleated GaN nanocolumns and growth of a continuous two-dimensional GaN layer are observed. The use of compliant Si substrates is a relevant approach for forming GaN-based semiconductor device heterostructures by plasma-assisted molecular beam epitaxy.
Субмонослойные квантовые точки InGaAs/GaAs, выращенные методом МОС-гидридной эпитаксии
Authors: Алешкин В.Я. , Байдусь Н.В. , Дубинов А.А. , Кудрявцев К.Е. , Некоркин С.М. , Круглов А.В. , Реунов Д.Г.
Published: July 2019

AbstractThe mode of the growth of InGaAs quantum dots by MOS-hydride epitaxy on GaAs substrates without a deviation and with a deviation of 2° is selected for laser structures emitting at wavelengths above 1.2 μm at room temperature. As a result, a quantum-dot density of 4 × 10^10 cm^–2 is achieved. Stimulated emission is observed in laser structures with seven layers of quantum dots at a wavelength of 1.06 μm at liquid-nitrogen temperature. The threshold power density of optical pumping is about 5 kW/cm^2.
Влияние лазерной обработки на прочность и прерывистую деформацию Портевена-Ле Шателье алюминиевого сплава
Authors: Шибков А.А. , Гасанов М.Ф. , Золотов А.Е. , Желтов М.А. , Денисов А.А. , Кочегаров С.С.
Published: July 2019

AbstractThe effect of surface processing by laser IR radiation on strength and Portevin–Le Chatelier serrated deformation of AlMg6 aluminum–magnesium alloy is experimentally studied. Laser processing consists in local “shots” on the surface at the nodes of a square grid in the gauge part of a flat sample. The conditions under which such laser processing causes an increase in the surface microhardness, ultimate tensile strength, and the critical strain of the first stress drop in the stress–strain curve; decreases the probability of deformation band formation; suppresses necking at the prefracture stage; and changes the main crack morphology. The possible mechanism of the effect of laser processing on band formation, serrated deformation, and alloy strength are discussed.
Об изменении реальной структуры кристаллов кремния, имплантированных ионами водорода, при их отжиге по данным трехкристальной рентгеновской дифрактометрии
Authors: Асадчиков В.Е. , Дьячкова И.Г. , Золотов Д.А. , Чуховский Ф.Н. , Сорокин Л.М.
Published: July 2019

AbstractIn this paper, we present the results of a three-crystal X-ray diffractometry (XRD) study of the state of a disturbed layer formed in silicon crystals by implantation of hydrogen ions with energies of 100 + 200 + 300 keV and a total dose of 2 × 10^16 cm^–2 during the subsequent heat exposure in the temperature range from 200 to 1100°C. Here, X-ray studies were performed in the three-crystal XRD scheme when the sample under consideration operates as a second stationary crystal with various fixed angular detuning α from the Bragg position while the third (perfect) crystal-analyzer sweeps the angular distribution of radiation diffracted by the second crystal. Based on a comparison of the shape of diffraction and diffuse maxima for the samples under study, a qualitative conclusion about a significant transformation of radiation defects at post-implantation annealing was derived.
Ловушки в нанокомпозитном слое кремний-диоксид кремния и их влияние на люминесцентные свойства
Authors: Дементьев П.А. , Иванова E.B. , Заморянская M.B.
Published: July 2019

The traps in thermal films of silicon dioxide and silicon dioxide with a nanocomposite layer on the surface were investigated by Kelvin-probe microscopy and cathode luminescence. In the layers, both electron traps and hole traps are observed. The effect of the charge state of electron traps on the luminescent properties of films is demonstrated. It is shown that in the presence of a nanocomposite layer in silicon dioxide films, the number of electron traps increases, but their activation energy remains close to the activation energy of traps in pure silicon dioxide, which suggests that the nature of the traps in such layers is similar.
Магнитные свойства допированных висмутом титанатов-пирохлоров иттербия и гольмия
Authors: Ринкевич А.Б. , Королева М.С. , Пийр И.В. , Перов Д.В.
Published: July 2019

AbstractBismuth-doped ytterbium and holmium titanates have been synthesized and their magnetic properties have been investigated. The magnetization curves and temperature dependences of the susceptibility in fields of up to 30 kOe at temperatures from 2 to 300 K have been obtained. The properties of the doped and undoped titanates have been compared. It has been established that the temperature dependences of the product of susceptibility and temperature contains a linear portion and the slope sign in these dependences changes upon doping for both the Ho_2Ti_2O_7 and Yb_2Ti_2O_7 titanates. Based on the investigated temperature dependences of the susceptibility, the magnetic dipole and exchange couplings in the titanates have been analyzed.
Откольная прочность ударно-разогретого гафния и уравнения состояния его полиморфных модификаций
Authors: Молодец А.М. , Голышев А.А.
Published: July 2019

he spall strength of hafnium heated by a loading shock wave to thousandths of temperatures and subjected to transformation into denser polymorphic modifications has been determined. The following problems are solved. The pressure profiles at the sample-soft barrier interface in the spall experiments with flat one-dimensional loading are measured. The equations of state of three polymorphic modifications of hafnium are constructed in the pressure range up to 100 GPa. The thermodynamic states of hafnium under the conditions of the performed experiments were calculated. These calculations, together with the results of measurements of pressure profiles, made it possible to determine the spall strength of hafnium heated in a shock compression-unloading cycle. The spall strength of hafnium was -4 (1) GPa at a temperature of 1680 (380) K. Mathematical modeling of spall experiments in the framework of a one-dimensional hydrocode was performed.
Формирование изображения краевой дислокации при аномальном прохождении рентгеновского излучения
Authors: Смирнова И.А. , Шулаков Е.В. , Суворов Э.В.
Published: July 2019

The image formation features of section and projection topograms of an edge dislocation normal to a crystal surface are considered for the case of X-ray anomalous transmission. Experimental images are analyzed using the numerical simulation of diffraction experiment. The new mechanism of an image formation of defects arranged near an output crystal surface is proposed. The distinctions of dislocation topographic images from local disorientation rosettes of reflecting planes are noted.
Спектры комбинационного рассеяния поликристаллических сульфатов лития, натрия и калия в предпереходной температурной области ниже структурного фазового перехода
Authors: Алиев А.Р. , Ахмедов И.Р. , Какагасанов М.Г. , Алиев З.А.
Published: July 2019

Molecular relaxation processes in lithium sulfate (Li2SO4), sodium sulfate (Na2SO4) and potassium sulfate (K2SO4) were studied by Raman spectroscopy. A decrease in the order parameter in the low-temperature phase is observed when approaching a phase transition, which, for example, is typical of a first-order phase transition close to the second. The existence of the pretransition region in the studied sulfates Li2SO4, Na2SO4 and K2SO4 was found.
Излучение света гетероструктурой CdMnTe/CdMgTe с узкими квантовыми ямами
Authors: Агекян В.Ф. , Борисов Е.В. , Серов А.Ю. , Философов Н.Г. , Karczewski G.
Published: July 2019

AbstractThe optical properties of the Cd_0.4Mn_0.4Te/Cd_0.5Mg_0.5Te heterostructure with quantum wells of 7 monolayers in thickness are studied. The temperature dependences of the integral intensity of luminescence of the barrier layer and quantum well and intracenter luminescence of manganese ions are determined, and the luminescence excitation spectra are measured. Numerous components corresponding to LO phonons of the CdTe, MgTe, and MnTe types are observed in the Raman scattering spectra.
Формирование упорядоченных кремниевых структур на поверхности графита
Authors: Ревегук А.А. , Петухов А.Е. , Вишнякова А.А. , Королева А.В. , Пудиков Д.А. , Жижин Е.В.
Published: July 2019

The work investigated the formation possibility of ordered silicon structures, including silicene, on the graphite substrates surface. The various conditions influence on the silicon atoms deposition on the final structure was also studied. Surface morphology information was obtained by atomic force microscopy, and the electronic structure was measured by Auger electron spectroscopy.
Об адсорбции газов на карбиде кремния: простые оценки
Authors: Давыдов С.Ю. , Посредник О.В.
Published: July 2019

Within the scope of two physically different approaches (solid-state and quantum-chemical) adsorption of nitrogen atom and nitrogen dioxide and ammonia mole-cules on silicon carbide are considered. In solid-state approach with the use of Haldane-Anderson model for the densities of state of 4H- and 6H-SiC polytypes it is shown that the binding energies for N and N2 are 6 and 3 eV correspondingly. In quantum-chemical approach for the two-atom surface molecule model for N adsorption the binding energy values are 6 eV for adsorption on C-face and 4 eV for adsorption on Si-face. It is demonstrated that the charge transfer between ad-sorbate and substrate for all the cases considered are negligible. It is proposed that as in the case of NH3 on Si(100) adsorption for SiC substrate ammonia molecule dissociates and H atoms passivate SiC sp3 orbitals.
Сверхтермостойкие полимерные нанокомпозиты на основе гетероциклических сеток: структура и свойства
Authors: Берштейн В.А. , Файнлейб А.М. , Якушев П.Н. , Кириленко Д.А. , Мельничук О.Г.
Published: July 2019

Nanocomposites based on heterocyclic polymer network, obtained from bisphthalonitrile and different (0.03-5.0 wt. %) contents of modified silicate montmorillonite (MMT) nanolayers, were studied. Their nanostructure, thermal, relaxation and elastic properties were characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDXS), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). DMA and TGA measurements were performed in both air and nitrogen mediums at temperatures from 20° to 600–900°C. Depending on MMT content, different extents of its exfoliation in the matrix, from single nanolayers to thin and “thick” MMT stacks were observed in the nanocomposites. The pronounced effects of constraining dynamics by nanoparticles and dynamic heterogeneity in the glass transition are shown. The possibilities for total suppression of glass transition and invariable elastic properties of nanocomposites within the temperature range from 20° to 600°C were shown. The studied nanocomposites manifest unique (for polymers) thermal properties, with glass transition temperature up to 570°С and satisfactory thermal stability, with retaining the material integrity, up to ~500°C in air and to ~900°C in N2 medium.
Математическое моделирование распространения верховых лесных пожаров при наличии противопожарных разрывов и заслонов
Authors: Марзаева В.И.
Published: July 2019

Using the method of mathematical modeling, the process of spreading forest fires in the presence of fire breaks and barriers consisting of hardwood trees was studied. Mathematically, this problem is reduced to solving the Reynolds equations for turbulent flow, taking into account chemical reactions. To obtain a discrete analogue, the control volume method was used. Using numerical calculations, we obtained the distributions of the fields of velocity, temperature, oxygen concentrations, volatile products of pyrolysis, combustion and volume fractions of the condensed phase. The model allowed us to obtain contours of the spread of forest fires, which depend on the stock and type of forest combustible materials, moisture content, velocity and direction of wind, etc. It was also possible to determine the dependence of the sizes of fire breaks and barriers on the above parameters, at which the crown fire stops spreading.
Численное моделирование термодинамических параметров высокопористой меди
Authors: Маевский К.К. , Кинеловский С.А.
Published: July 2019

The modified equation of state is proposed for the calculation of thermodynamically equilibrium model TEС2 to improve the reliability of the description of thermodynamic parameters of shock-wave loading of pure materials and heterogeneous mixtures of different porosity. The parameters of the thermally consistent equation of state are determined for copper. A reliable description of the shock-wave loading of copper is obtained for a small number of fitting parameters determined by the experimental data. The thermodynamic parameters for copper of different porosity are modeled, the compression and temperature values along the shock adiabate are determined; the heat capacity value along the normal isobar is calculated. The results of calculations are compared with the known experimental results of different authors.
Процессы захвата и диссоциативного захвата одного электрона при взаимодействии двухзарядных ионов с молекулами CO
Authors: Басалаев А.А. , Кузьмичев В.В. , Панов М.Н. , Смирнов О.В.
Published: July 2019

AbstractThe absolute cross sections of single-electron capture and single-electron capture with dissociation in the interaction between incident He^2+, C^2+, N^2+, and O^2+ ions with energies from 6.4 to 36.4 keV and СО molecules were measured. It is demonstrated that the cross section of dissociative capture is much larger than the cross section of single-electron capture for O^2+ projectile ions. A qualitative explanation for this effect is provided.
Генерация кластеров лития в плазменном потоке гелия
Authors: Попов А.В. , Попов В.А.
Published: July 2019

The formation of lithium clusters in a helium stream is considered in the framework of the method taking into account the width of energy levels. It is shown that lithium atoms form clusters consisting only of lithium in the plasma stream of inert helium. Long-lived excitations of lithium clusters with interatomic distances of 13 Bohr radii were found in addition to those with interatomic distances corresponding to interatomic distances of the equilibrium state. However, such systems transit to the ground state, or disintegrate when the excitation is ended. Long-lived Li-He systems in the condition of external excitations were found, but rapidly losing helium when these excitations are ended.
Об инкрементах неустойчивости волн различной симметрии на движущейся относительно материальной среды объемно заряженной струе
Authors: Григорьев А.И. , Ширяева С.О. , Михеев Г.Е.
Published: July 2019

The increments of instability of capillary waves with arbitrary symmetry (with arbitrary azimuthal numbers ) on the surface of a volume charged cylindrical jet of an ideal incompressible dielectric fluid moving relative to an ideal incompressible material dielectric medium are investigated. It is shown that at not too high velocities of the jet motion, with an increase in the volume charge density, the axisymmetric mode ( m=0) becomes unstable first, then the bending mode ( m=1), and then the bending-deformation mode (m=2 ).This sequence of realization of the instability of azimuthal modes and determines the patterns of fragmentation of charged jets in the experiments. At jet speeds comparable to the critical for the realization of aerodynamic instability, the first loses stability mode whis . For all azimuthal modes, the dependences of the maximum increments on the wave numbers are determined.
Экспериментально-расчетное исследование высокоскоростного соударения алюминиевого ударника со сплошной и сетчатой преградой
Authors: Кузьмин В.А. , Герасимов С.И. , Зубанков А.В. , Сироткина А.Г. , Акашева Е.П. , Герасимова Р.В.
Published: July 2019

The results of the computational and experimental study of the features of the impact of the impactor with the barrier simulating the screen shield of the spacecraft are presented, the pictures of fragmentation of the impactor and the barrier are presented. Numerical calculations were performed using the SPH (Smoothed Particle Hydrodynamics) method. In the experiment, the impactor was accelerated using a two-stage light-gas gun, the state of the barrier and the impactor at the time of their interaction was controlled using x-ray and high-speed video camera. Start-up of the recording equipment was carried out by means of induction sections. The comparative analysis of results of numerical calculation and experiment is given.
Особенности формирования и структуры ленгмюровских пленок титаната бария
Authors: Кузьменко А.П. , Чухаева И.В. , Абакумов П.В.
Published: July 2019

With the use of the Langmuir-Blodgett (LB) method on the KSV NIMA 2002 plant, ferro-electric films of the stabilized barium titanate (ST BTO) from colloidal system of sodium oleate aqueous solution have been produced, which were studied with small angle X-ray scattering and dynamic light scattering techniques. Coagulants with the most characteristic hydrodynamic diameter ~ 200 nm are found and the physical model of their formation from barium titanate nanoparticles (~ 20 nm) in this colloidal system is proposed.
By means of compression-expansion isotherms with the use of a MicroBAM micro-scope and the device for measurement of surface potential SPOT, optimum parameters of sedimentation are determined, which made it possible to produce uniform ferroelectric films with ST BTO particles of ~ 20 nm in size and a forbidden band width of 3.6 eV.
With scanning probe and electron microscopy, vibrational and X-ray photoelectron spectroscopy, and also X-ray diffractometry, topological and structural features and distri-bution of chemical elements in the produced films on different substrates have been stud-ied.