bluuebunny/crossref_metadata_2025 huggingface dataset:
Storability, Quality Changes, and General Postharvest Behavior of Dudaim Melon Harvested at Two Maturity Stages
Authors: Hatami Mohsen , Kalantari Siamak , Soltani Forouzandeh , Beaulieu John C.
Published: May 2019

Dudaim melon (Cucumis melo Group Dudaim) is a unique edible melon for which few postharvest physiology studies have been conducted. To investigate the postharvest behavior of dudaim melon, two cultivars (Zangi-Abad and Kermanshah) were planted, tagged at anthesis, and harvested at two maturity stages: 21 and 28 d after anthesis (DAA). Harvested fruit were stored at 5 or 13 °C for up to 3 weeks and various quality parameters including color, firmness, titratable acidity (TA), total soluble solids (TSS), weight loss, chilling injury (CI), ethylene production, protein content, glucose content, fructose content, sucrose content, and maltose content were assessed during storage. After 3 weeks of storage at 13 °C, early-harvested fruit (21 DAA) had relatively similar color values (L*, lightness; a*, green–red tones; b*, blue–yellow tones) and TA compared with late-harvested fruit (28 DAA); however, some quality traits, such as TSS, were not similar. Ethylene content decreased initially after harvest and then started to increase during storage at 13 °C. For most treatments, glucose and fructose contents decreased whereas sucrose and maltose contents increased with advancing maturity. Increased ethylene production, in concert with color development at 13 °C, similar to ripe fruit, and the changing balance of measured mono- and disaccharide sugars in harvested fruit likely indicates ‘Kermanshah’ is climacteric. Results for ‘Zangi-Abad’ were not as definitive. Dudaim melon fruit can be harvested at an optimum stage of maturity, similar to known climacteric melon fruit, and then allowed to ripen at proper storage temperatures before consumption. Based on the results of this study, we recommend that harvest at 21 DAA and storage at a nonchilling temperature such as 13 °C are the optimal stage and temperature for long storage purposes.
Material suplementar - Conforto térmico de um cômodo construído com diferentes tipos de revestimentos
Authors: Pereira Daniel Machado Alves , Prat Bernat Vinolas , Teixeira Flaviana Tavares Vieira
Published: May 2019

O conforto térmico mantém uma íntima relação com a qualidade de vida e a produtividade de todos os seres vivos, pois está relacionado com o seu grau de satisfação e acomodação com a temperatura ambiente. Assim, o presente artigo objetiva demonstrar como os materiais utilizados em uma construção interferem na variação da temperatura, consequentemente no conforto térmico e na ecoeficiência de um ambiente. Para isto criou-se uma planilha de dados, que mostra a variação da temperatura ao longo de um dia em um cômodo construído de 16 m². Com estes dados é possível obter informações sobre como o tipo de bloco, reboco e materiais isolantes interferem no conforto térmico de um edifício. A análise dos dados não mostrou grandes variações de temperatura para blocos comumente utilizados, contudo, concluiu-se que dependendo do material utilizado na construção pode-se interferir na sua ecoeficiência.
Percepção sobre o licenciamento ambiental e expectativas sobre a atuação do Núcleo de Controle Ambiental na etapa de monitoramento no Estado de Minas Gerais
Authors: Oliveira Rosane de Souza , Almeida Maria Rita Raimundo e
Published: May 2019

No Brasil, a Política Nacional do Meio Ambiente de 1981 é um importante marco na inclusão das questões ambientais nas políticas públicas e prevê, como um de seus instrumentos, o licenciamento ambiental, que é construído pelas Licenças Prévia, de Instalação e de Operação. Minas Gerais foi um estado pioneiro na utilização do automonitoramento para o acompanhamento dos empreendimentos no pós-licenciamento, porém, enfrenta falhas na sua prática, comprometendo o processo de Avaliação de Impactos Ambientais (AIA). O modelo estabelecido pelo estado na tentativa de superar estes problemas baseia-se na implantação do Núcleo de Controle Ambiental (NUCAM), atuando diretamente nesta etapa. Desta forma, este trabalho teve como objetivo verificar as percepções e expectativas dos servidores do órgão ambiental mineiro com a implementação desse núcleo. Para tal, foram realizadas entrevistas com servidores da Superintendência Regional de Meio Ambiente Triângulo Mineiro e Alto Paranaíba (Supram TMAP). Os servidores da Supram TMAP entrevistados demonstraram acreditar que com a atuação do NUCAM os problemas da etapa de pós-licenciamento irão ser amenizados, porém, é cedo para afirmar que serão sanados. De qualquer modo, o núcleo já se tornou um importante ponto de partida para possibilitar que a AIA cumpra seu papel, sendo necessários futuros acompanhamentos.
Resíduos sólidos urbanos: viabilidade técnica do processo produtivo do biometano
Authors: Soares Rayme Vasconcellos , Lopes Jerisnaldo Matos
Published: May 2019

Fazendo uso das abordagens qualitativa e quantitativa, este trabalho é lastrado em investigação bibliográfica e documental, empregando a pesquisa exploratória e explicativa, de modo a possibilitar a análise da viabilidade técnica do processo produtivo do biometano a partir de resíduos sólidos urbanos, considerando o aterro sanitário como estrutura fundamental para a disposição dos resíduos, matéria-prima básica para o processo de produção do biogás. Há de se validar, contudo, a eficiência de um aterro sanitário projetado adequadamente, cuja composição possui, dentre outros elementos o sistema de drenagem de águas, o sistema de drenagem de gases, a camada de cobertura e um sistema de monitoramento, que visa a garantir a preservação do meio ambiente, a salubridade da população em torno e a segurança da obra, basicamente. O biometano é resultado da purificação do biogás que compreende a dessulfurização, o processo de secagem e a remoção do CO2, visando a alcançar um teor de metano de mais de 95%.
O manejo dos resíduos florestais afeta a produção de biomassa e a sustentabilidade de povoamentos de Eucalyptus sp.
Authors: Momolli Dione Richer , Schumacher Mauro Valdir
Published: May 2019

O resíduo da colheita florestal serve como fonte de matéria orgânica e nutrientes ao desenvolvimento das futuras rotações, além disso, atua na proteção do solo evitando a erosão, a exposição direta aos raios solares e a compactação, aumentando a capacidade de retenção hídrica. A biota do solo possui o papel de decompor e mineralizar os nutrientes presentes na matéria orgânica. Através desse processo acelera-se a ciclagem dos nutrientes, liberando-os para posterior absorção pelas raízes das árvores. O descascamento da tora a campo é uma forma de manejo que minimiza o percentual de nutrientes exportados. O objetivo dessa revisão bibliográfica é abordar os efeitos do manejo dos resíduos da colheita na produção de biomassa e na sustentabilidade das plantações de eucalipto.
Analysis of Land Use Land Cover in Annapurna Conservation Area in Gandaki Province, Nepal using Vegetation Index and Land Use Land Cover Datasets
Authors: Pokhrel Shiva , Sherpa Chungla
Published: May 2019

Conservation areas are originally well-known for protecting landscape features and wildlife. They are playing key role in conserving and providing a wide range of ecosystem services, social, economic and cultural benefits as well as vital places for climate mitigation and adaptation. We have analyzed decadal changes in land cover and status of vegetation cover in the conservation area using both national level available data on land use land cover (LULC) changes (1990-2010) and normalized difference vegetation index (NDVI) (2010-2018) in Annapurna conservation area. LULC showed the barren land as the most dominant land cover types in all three different time series 1990, 2000 and 2010 with followed by snow cover, grassland, forest, agriculture and water body. The highest NDVI values were observed at Southern, Southwestern and Southeastern part of conservation area consisting of forest area, shrub land and grassland while toward low to negative in the upper middle to the Northern part of the conservation area.
Tec1 Proteininin NTH1 Promotoruna Bağlanmasının Moleküler Modellemesi
Authors: TURGUT GENÇ Tulay , ÇAKAS Selen
Published: May 2019

Saccharomyces cerevisiae maya hücrelerinde trehaloz molekülü enerji kaynağı ve stres metaboliti olarak görev yapmaktadır. Trehalozun sentezinde ve yıkımında görevli proteinlerin ve ilgili genlerinin ekspresyonları sıkı bir şekilde kontrol edilmektedir. Stres koşullarında sentezlenen trehalozun yıkımında görev alan NTH1 geni transkrispsiyonel ve post-translasyonel olarak regüle edilmektedir. Özellikle transkripsiyonel regülasyonda rol alan transkripsiyon faktörlerinin tümü henüz bilinmemektedir. Bu nedenle çalışmada öncelikle NTH1 promotor bölgesinin biyoinformatik analizi yapıldı ve bağlanma olasılığı bulunan transkripsiyon faktörleri belirlendi. Bu faktörlerden Tec1 transkripsiyon faktörünün NTH1 promotoruna potansiyel üç boyutlu NTH1 promotor-Tec1p bağlanma modeli farklı veri tabanları ve DNA-protein docking programları kullanılarak oluşturuldu. Elde edilen modelleme üzerinde yapılan ölçümlerde Tec1 proteinin NTH1 promotoruna bağlanma olasılığının kuvvetli olduğu belirlendi. Ayrıca Tec1 proteininin TEA-DNA bağlanma bölgesinin S. cerevisiae ve diğer canlılarda yapılan BLAST analizi sonucunda TEA-DNA bağlanma bölgesinde bulunan 22 amino asitin tüm canlılarda % 100 korunduğu tespit edildi.
Some New Results on Soft n-T4 Spaces
Authors: GÖÇÜR Orhan
Published: May 2019

Göçür and Kopuzlu showed that any soft T₄ space, may not be a soft T₂ space (also may not be a soft T₃ space). In this case, they described a new soft separation axiom which is called soft n-T₄ space. Then they indicated that any soft n-T₄ space is soft T₃ space also (Göçür and Kopuzlu, 2015b). In the present paper we showed that if (X,τ,E) is a soft n-T₄ space, topological space (X,τ_e )  is a T₄ space for all e∈ E. Then we indicated that any Soft Metric space is also soft n-T₄ space. Consequently, we indicated that any Soft Metric space ⟹ Soft n-T_4 space ⟹ Soft T_3 space ⟹ Soft T_2 space ⟹ soft T_1 space ⟹ soft T_0 space also.
Akkeçilerde İnsülin Benzeri Büyüme Faktörü-I’in (IGF-I) Laktasyon Dönemindeki Değişimi
Authors: TERZİ Naciye Melis , PEHLİVAN Erkan , DELLAL Gürsel
Published: May 2019

Bu araştırmada, Ankara Üniversitesi Ziraat Fakültesi Zootekni Bölümü Hayvancılık İşletmesinde yetiştirilen 6 baş 2 yaşlı ve 5 baş 3 yaşlı olmak üzere toplam 11 baş dişi Akkeçide laktasyon döneminde IGF-I’in değişimi incelenmiştir. Çalışmada, IGF-I konsantrasyonlarını belirlemek için laktasyon dönemi boyunca keçilerin boyun toplardamarından her iki haftada bir düzenli olarak kan örnekleri alınmıştır. Kan örnekleri 4000 devir/dak’da 5 dakika süreyle santrifüj edilmiş ve serumlar -20 °C’de laboratuvar analizleri gerçekleştirilene kadar muhafaza edilmiştir. Kan serumunda IGF-I analizleri enzim immunoassay (EIA) yöntemiyle gerçekleştirilmiştir. Araştırmanın gerçekleştirildiği döneme ait meteorolojik veriler Meteoroloji Genel Müdürlüğü’nden temin edilmiş ve bu değerlerden sıcaklık-nem indeksi (SNİ) hesaplanmıştır. Araştırmada, IGF-I konsantrasyonları bakımından dönemler ve yaş grupları arasındaki farklılıklar, tekrarlanan ölçümlü varyans analizi tekniği ile değerlendirilmiştir. İstatistik analiz sonucunda, sadece incelenen dönemler arasındaki farklılıklar istatistik olarak önemli (P<0.01) bulunmuştur. Sonuç olarak, Akkeçilerde laktasyon döneminde, IGF-I konsantrasyonlarının fotoperiyot değişimlerinden önemli düzeyde etkilendiği ve gün uzunluğundaki artışa bağlı olarak IGF-I salınımının arttığı belirlenmiştir.
Dış Göçlerin Mevsimlik Tarım İşçiliği Üzerine Etkilerinin Değerlendirilmesi
Authors: BAYRAMOĞLU Zeki , BOZDEMİR Merve
Published: May 2019

Bu çalışma, Türkiye’nin mevsimlik tarım işçiliği ve aldığı dış göçler üzerine yapılan alan araştırmaları incelenerek; Türkiye’nin aldığı dış göçlerin mevsimlik tarım işçiliğine etkilerinin belirlenmesi ve mevsimlik tarım işçiliğinde meydana gelen sosyo-ekonomik sorunların tespiti amacıyla gerçekleştirilmiştir. 1951 yılında Cenevre Sözleşmesinin imzalanmasıyla birlikte Türkiye mültecilere iltica hakkı tanımış ve sözleşmede bazı özel şartlar belirlemiştir. Cenevre sözleşmesinden sonra yaşanan savaşlar, iç çatışmalar, doğal afetler gibi gerekçelerle insanların ikamet ettikleri yerleşim yerlerini terk etmek zorunda kalmaları ya da göç etmeye zorlanmaları sebebiyle Türkiye Ortadoğu’dan çok sayıda göçmen almıştır. Bu durum mevsimlik tarım işçilerinin sayısında özellikle 1950’li yıllardan günümüze hızlı bir artış meydana gelmesine neden olmuştur. 1980 ve 1990 yılları arasında yaşanan dış göçlerin etkisiyle mevsimlik tarım işçilerinin sayısı milyonları bulmuştur. Bu zaman dilimi sonrasında mevsimlik tarım işçiliği marjinal bir emek biçimi olmaktan çıkmıştır. 2000’li yıllarda ise göçmen mevsimlik tarım işçilerinin sayısı önemli boyutlara ulaşmıştır. Özellikle 2011 yılından itibaren çoğunluğu Suriyeli işçilerden oluşan tarımsal göçmen işgücü çeşitli üretim süreçlerinde yerli mevsimlik işgücünün yerini almıştır. Bu çalışma kapsamında dış göçlerin mevsimlik tarım işçiliği üzerine etkileri değerlendirilmiş ve çalışmanın sonunda piyasaya yönelik politika önerilerinde bulunmuştur.
3-Boyutlu Minkowski Uzayında Timelike Binormalli Spacelike Eğrinin Tabii Liftini Asimptotik Kabul Eden Yüzey Ailesi
Authors: ERGÜN Evren , BAYRAM Ergin
Published: May 2019

timelike binormalli spacelike bir
eğri,  ise  nın tabii lifti olsun. Bu
çalışmada, 3 boyutlu Minkowski uzayında  yi ortak asimptotik eğri kabul
eden yüzey ailesi elde edildi.  nin oluşturulan yüzeyler üzerinde
asimptotik eğri olması için gerekli şartlar bulundu. Bazı örnekler verildi.
Anadolu Orkidesi’nde (Orchis anatolica Boiss.) Ribozomal DNA’nın Transkripsiyonu Yapılan İç Ara Bölgelerinin (ITS) Özellikleri
Authors: HÜRKAN Kaan
Published: May 2019

Orkideler (Orchidaceae), yeryüzünün neredeyse tamamında yayılış gösteren ve çiçekli bitkiler içerisinde en çok tür içeren ikinci familyadır. Bu kalabalık bitki grubunun sınıflandırılması ve filogenetiğinin ortaya çıkarılmasında sadece morfolojiye dayalı yöntemler yetersiz kalmaktadır. Bu çalışmada Orchis anatolica Boiss. türünün çekirdek DNA’sının ITS bölgesi dizilenerek DNA barkodu ortaya çıkarılmış ve bu veri analiz edilerek Pseudorchis albida subsp. straminea (Fernald) Á.Löve & D.Löve, Orchis italica Poir., Orchis anthropophora All., Orchis simia Lam., Orchis purpurea Huds., Orchis militaris Sm., Orchis adenocheila Czerniak, Orchis pallens L., Orchis mascula Crantz, Orchis mascula subsp. pinetorum Boiss. & Kotschy ve Orchis spitzelii Saut. ex W.D.J.Koch türleri ile filogenetik ilişkileri incelenmiştir. Çalışma sonucunda ITS dizisinin tamamının çalışılan Orchis türleri arasında yeterli seviyede ayrım yapabildiği ve bu cins içerisinde yapılacak daha detaylı çalışmalar için kullanılmaya elverişli olduğu sonucuna varılmıştır.
MiR-137 Restricts the Viability and Migration of HTR-8/SVneo Cells by Downregulating FNDC5 in Gestational Diabetes Mellitus
Authors: Peng Hai-Yan , Li Ming-Qing , Li Hua-Ping
Published: May 2019

Background:

An increasing number of studies have described the
pathological changes of placenta tissues in gestational diabetes mellitus (GDM),
although the underlying mechanisms involved in this process remain uncertain. The aim
of the present study was to verify the possible role of microRNA-137 (miR)-137 and
FNDC5 in regulating the biological function of trophoblasts in high glucose (HG)
conditions during the GDM period.

Methods:

Expression levels of miR-137 and FNDC5 were measured in placenta
specimens, the HG-treated trophoblast cell line HTR-8/SVneo and miR-137-
overexpressing HTR-8/SVneo cells using reverse transcription quantitative-PCR or
western blotting. The viability of HTR-8/SVneo cells was tested using a Cell Counting kit-
8 (CCK8) assay, with cell migration assessed using scratch and transwell assays.

Results:

It was observed that the expression levels of miR-137 were increased and the
expression levels of FNDC5 were decreased in the placenta tissues of women with
severe GDM and in HG-exposed HTR-8/SVneo cells. In addition, upregulating miR-137
in HTR-8/SVneo cells downregulated the expression levels of FNDC5. The viability and
migration of HTR-8/SVneo cells were suppressed by increased miR-137 expression
levels, and upregulating FNDC5 in miR-137-overexpressing HTR-8/SVneo cells resulted
in the reversal of all these effects.

Conclusion:

The data from the present study suggest that miR-137 suppresses the
viability and migration of trophoblasts via downregulating FNDC5 in GDM, which may
contribute to the pathology of placenta tissues and occurrence of adverse pregnancy
outcomes.
Sperm Quality in Mouse After Exposure to Low Doses of TCDD
Authors: Elsayed Heba Yehia Anwar , Borroto Esvieta Tenorio , Pliego Alberto Barbabosa , Dibarrat Jorge Acosta , Ramirez Fabiola Rivera , Chagoyán Juan Carlos Vázquez , Salas Nazario Pescador , Diaz-Albiter Hector
Published: May 2019

Background:

In the last decade, the harmful use of dioxin has been demonstrated in human
health and in the whole environment. It is well known among scientists that 2, 3, 7, 8-tetrachloro
dibenzo-p-dioxin (TCDD) is an environmental pollutant that causes endocrine disruption, which causes
male reproductive toxicity.

Objective:

The objective of the present study was to evaluate the toxicity effect of low doses of TCDD
in male CD1 mice.

Materials and Methods:

Three concentrations of TCDD (0.375, 0.75, 1.5 mg / kg) were analyzed and
the effects on spermatozoa were evaluated 10 days after oral administration of the product. As
bioindicators of TCDD toxicity, an exhaustive analysis of several spermatic parameters including
motility, vitality, count, morphology and viability, flow cytometry was used to determine the affected
sperm population by cytotoxicity and apoptosis. In addition, a morphometric analysis of testicles was
performed.

Results:

The results show that the body weight of the treated animals was reduced in medium and high
doses (0.75, 1.5 mg / kg) with respect to the control groups. In the groups treated with TCDD, the
abnormal head of the sperm increased by 52.5% more than the control group. Significant differences in
apoptosis were observed between the negative control and vehicle control, including the median dose
(0.75 mg / kg).

Conclusion:

It is concluded that at these low doses there was an impact on the quality of the mouse
sperm, adding an effect on apoptosis and cytotoxicity of sperm exposed to these doses of TCDD.
Термоэлектрические свойства нанокомпозитного Bi-=SUB=-0.45-=/SUB=-Sb-=SUB=-1.55-=/SUB=-Te-=SUB=-2.985-=/SUB=- с микрочастицами SiO-=SUB=-2-=/SUB=-
Authors: Шабалдин А.А. , Константинов П.П. , Курдюков Д.А. , Лукьянова Л.Н. , Самунин А.Ю. , Стовпяга Е.Ю. , Бурков А.Т.
Published: May 2019

AbstractNanocomposite thermoelectrics based on Bi_0.45Sb_1.55Te_2.985 solid solution of p -type conductivity are fabricated by the hot pressing of nanopowders of this solid solution with the addition of SiO_2 microparticles. Investigations of the thermoelectric properties show that the thermoelectric power of the nanocomposites increases in a wide temperature range of 80–420 K, while the thermal conductivity considerably decreases at 80–320 K, which, despite a decrease in the electrical conductivity, leads to an increase in the thermoelectric efficiency in the nanostructured material without the SiO_2 addition by almost 50% (at 300 K). When adding SiO_2, the efficiency decreases. The initial thermoelectric fabricated without nanostructuring, in which the maximal thermoelectric figure of merit ZT = 1 at 390 K, is most efficient at temperatures above 350 K.
Криогенный термоэлектрический модуль для рабочего интервала температур ниже 90 K
Authors: Сидоренко Н.А. , Дашевский З.М.
Published: May 2019

It is considered the possibility of creating thermoelectric coolers for operating temperatures below 90 K. For these temperatures it is not possible to use a standard circuit of a thermoelement, consisting of two n- and p-semiconductor legs, connected in a series electrical circuit. In the area of cryogenic temperatures there is only an effective thermoelectric material of n-type conductivity, based on solid solutions Bi−Sb. In this case thermoelements composed of thermoelectric n-type leg and a passive leg, based on high temperature superconductor (HTSC) were studied. A thermoelectric cooler (module), consisting of six n-type legs (extruded crystals Bi0.91Sb0.09 ) and passive legs based on HTSC (YBa2Cu3O(7−x) ) films was designed. A magnetic field was used to increase thermoelectric figure of merit ZT of the cryogenic module. For created cryogenic module at hot side temperature Th = 80 K, a current I = 6.4 A and a voltage U = 0.10 V the maximum value of temperature drop > 13.5 K and a maximum cooling capacity Qc > 0.36 W were achieved.
Моделирование процесса усадки термоэлектриков при искровом плазменном спекании на примере Ge-Si
Authors: Тукмакова А.С. , Самусевич К.Л. , Новотельнова А.В. , Тхоржевский И.Л. , Макарова Е.С.
Published: May 2019

The densification of Ge-Si within spark plasma sintering has been simulated. The simulation was based on finite elements method and implemented in Comsol Multiphysics. The model of mechanical processes was based on the simulation results published earlier for metal and ceramic powder materials. The model included plastic and elastic deformation description, impact of porosity on electrical, thermal and mechanical properties. The pressure field in the sample has been calculated. The change of sample diameter due to the expansion and compression has been obtained for the soaking period.
Исследование энергетического спектра кристаллов Si:Mg методом DLTS
Authors: Ярыкин Н.А. , Шуман В.Б. , Порцель Л.М. , Лодыгин А.Н. , Астров Ю.А. , Абросимов Н.В. , Weber J.
Published: May 2019

AbstractElectrically active centers in n -type magnesium-doped silicon crystals are studied by deep-level transient spectroscopy (DLTS). Magnesium is introduced by diffusion from a metal film on the surface at 1100°C. It is found that two levels with a similar concentration of ~6 × 10^14 cm^–3 dominate in the DLTS spectrum; the value approximately corresponds to the interstitial magnesium (Mg_ i ) concentration expected from diffusion conditions and published data on the Hall effect. The dependence of the electron emission rate from these levels on the electric-field strength agrees qualitatively with the Poole–Frenkel effect, which indicates the donor nature of both levels, although the absolute value of the effect differs from theoretical value. The activation energies of these levels found by the extrapolation of emission rates measured at various temperatures to zero field are 112 and 252 meV, which coincides within the accuracy with energies of ground states of the first and second donor levels of Mg determined previously from optical absorption. Thus, it is shown that when using high-quality initial material and the selected diffusion mode, interstitial magnesium atoms are the dominant centers with levels in the upper half of the band gap.
Характер изменения обратного тока в туннельных МДП-диодах с фторидом кальция на Si(111) при создании дополнительного оксидного слоя
Authors: Банщиков А.Г. , Илларионов Ю.Ю. , Векслер М.И. , Wachter S. , Соколов Н.С.
Published: May 2019

AbstractThe currents flowing in metal–CaF_2– n -Si and metal–SiO_2–CaF_2– n -Si structures with the same (about 1.5 nm) fluoride thickness are compared in the reverse-bias mode. It is revealed that the current in the case of a two-layer dielectric can be notably higher within a certain voltage range. Such unexpected behavior is associated with the coexistence of both electron and hole components of the current as well as with the configuration of the SiO_2–CaF_2 barrier through which tunneling occurs. The results of measurements and explanatory simulation data are presented.
Модель распада сплава Fe-Cu с концентрационно-зависящими межатомными взаимодействиями
Authors: Разумов И.К. , Шмаков И.Г.
Published: May 2019

AbstractThe thermodynamics and kinetics of decomposition of a Fe–Cu alloy are investigated in the context of a simple ab initio parameterization model taking into account the concentration dependence of the magnetic contribution to the free energy. It is shown that taking into account a difference between the short-range and long-range magnetic orders near the Curie temperature is very important for calculating the solubility of copper in iron. The solubility of copper in bcc iron and the stability limit of a homogeneous state (physical spinodal) are evaluated via the kinetic Monte Carlo method. The impact of structural defects (dislocations and grain boundaries) on these curves, as well as on the kinetic time–temperature—transformation (TTT) diagram, is also discussed.
Тепловое расширение ограниченных полупроводниковых твердых растворов Ag-=SUB=-x-=/SUB=-Pb-=SUB=-1-x-=/SUB=-S
Authors: Садовников С.И.
Published: May 2019

Single-phase powders of AgxPb1-xS cubic solid solutions with a maximum relative silver content up to x = 0.12 were synthesized from aqueous solutions of lead acetate and silver nitrate in the presence of a sulfidizing agent, complexing and stabilizing agents. Thermal expansion of synthesized semiconductor solid solutions AgxPb1-xS was measured for the first time by dilatometry in the temperature range of 295-580 K. It is shown that the replacement of lead atoms by silver atoms in AgxPb1-xS leads to a small decrease in the thermal expansion coefficient associated with a change in the anharmonicity of atomic oscillations.
Отклик на однородное электрическое поле в расчетах электронной структуры кристаллов с базисом локализованных орбиталей
Authors: Гордиенко А.Б. , Филиппов Д.И.
Published: May 2019

The calculation of the response to an external, homogeneous electric field is considered within the framework of electronic structure calculations using the basis of localized pseudoatomic orbitals. The basic equations have been derived with accounting for the incompleteness and nonorthogonality of the basis, as well as the computational formulas for the dielectric tensor and dynamic charges. The results of the implementation are discussed by the example of calculations performed for compounds of various type.
Электрическая поляризация неоднородно напряженных редкоземельных кристаллов со структурой граната и их пленок
Authors: Попов А.И. , Сабденов Ч.К.
Published: May 2019

The effect of non-uniform deformations on emergence of electric polarization in rare-earth garnets was analyzed. The research of polarization of rare-earth subsystem in inhomogeneously stressed areas arising in the presence of edge and screw dislocations was conducted. The distribution of electric polarization inside inhomogeneously strained rare-earth garnet films was studied. This work was supported by the RFBR grant № 16-29-14005
Индуцированный квазидинамический беспорядок в структуре имплантированного ионами рения кварцевого стекла
Authors: Зацепин А.Ф. , Бирюков Д.Ю. , Гаврилов Н.В. , Штанг Т.В. , Koubisy M.S.I. , Парулин Р.А.
Published: May 2019

The ultraviolet (UV) absorption spectra of quartz KUVI glasses (type IV) irradiated with rhenium ions with an energy of 30 keV are studied. It was found that with increasing ion fluence (510^15 – 510^17 cm^ 2), a characteristic fan-shaped broadening of the optical absorption edge of glasses is observed. The results are interpreted within the framework of the generalized Urbach rule (approximation of quasidynamic disorder induced by ion irradiation). Based on the dose dependence of the characteristic Urbach energy, an estimate was made of the effective cross section for the process of radiative disordering of the glass matrix. It was found that this value varies within 1.0710^-17 cm^2 –1.210^-18 cm^2 with increasing fluence. The optical gap width of the implanted samples was determined by the Tauts method for direct allowed interband transitions. Based on the principle of equivalence of static and dynamic structural disorder, a ratio of the constants of second-order deformation potentials was found, which determines the relationship between the Urbach energy and the optical gap width of silica glass matrix SiO2.
This work was supported by the Ministry of Education and Science of the Russian Federation (Government Task No. 3.1485.2017 / 4.6) and the Russian Government (Act 211, Contract No. 02.A03.21.0006).
Магнитные свойства топологического изолятора Bi-=SUB=-2-=/SUB=-Se-=SUB=-3-=/SUB=-, легированного железом
Authors: Шевченко Е.В. , Хачатрян А.Ш. , Антоненко А.О. , Чарная Е.В. , Наумов С.В. , Марченков В.В. , Чистяков В.В. , Lee M.K. , Chang L.-J.
Published: May 2019

AbstractWe study the dc magnetization of a Bi_1.94Fe_0.06Se_3 single crystal in the temperature range of 1.9 to 400 K in applied magnetic fields up to 70 kOe for two sample orientations in the applied field. We register three magnetic phase transitions and observe considerable anisotropy of the magnetic properties. The coercive force varies with temperature in a nonmonotonic manner. For the sample in a paramagnetic state, we estimate its magnetic moment per iron atom; its Curie–Weiss temperature is found to be negative. Arrot–Belov plots are constructed.
Парамагнитные ионы в легированном европием искаженном перовските YAlO-=SUB=-3-=/SUB=-
Authors: Важенин В.А. , Потапов А.П. , Петросян А.Г. , Асатрян Г.Р. , Фокин А.В. , Артёмов М.Ю.
Published: May 2019

In yttrium orthoaluminate crystals doped with the 151Eu isotope, the paramagnetic centers Eu2+, Cr3+, Gd3+, and Mo3+ have been detected. The fine structure parameters of the spin Hamiltonian of these centers were determined or refined. The account of the orientational behavior of previously unobserved forbidden transitions has been taken for the Cr3+ centers. It is shown that two Mo3+ signals that are detected in magnetic fields parallel to the crystallographic axes do not belong to different molybdenum centers, but are two intra-doublet transitions of the same center.
Electronic structures and magnetic properties of transition metal doped CsPbI-=SUB=-3-=/SUB=- perovskite compounds by first-principles calculation -=SUP=-*-=/SUP=-
Authors: Suzuki Atsushi , Oku Takeo
Published: May 2019

AbstractTransition metal doped cesium lead halide (CsPbI_3) perovskite compounds were studied for application in photovoltaic solar cells. Electronic structures, chemical shifts of ^207Pb and ^127I-NMR, vibration modes in infrared and Raman spectra of transition metals (Mn^2+, Fe^2+ or Cu^2+)-doped CsPbI_3 perovskite compounds were studied by the first-principles calculation using density functional theory. The CsPb(Fe)I_3 perovskite crystals had a slight perturbation of crystal field in the coordination structure. The electron density distribution was delocalized on the 5 p orbital of I atom, the 3 d orbital of Fe atom and the 6 p orbital of Pb atom. The first excited process was based on ligand metal charge transfer from the 5 p orbital on I atom to the 3 d orbital of Fe atom. The chemical shifts of ^127I-NMR were associated with the electron correlation of electron-nuclear spin interaction and nuclear quadrupole interactions based on electron field graduate. The asymmetric vibrations of Pb–I bonds stretching mode related to electron conductivity with scattering of the carrier diffusion as phonon effectiveness. The slight perturbation of the coordination structure in the CsPb(Fe)I_3 perovskite crystal will improve the photovoltaic and optical properties.
Исследование кинетики твердофазного перехода в тетракозане С-=SUB=-24-=/SUB=-Н-=SUB=-50-=/SUB=- методом высокоразрешающей синхротронной рентгеновской порошковой дифракции
Authors: Марихин B.A. , Дороватовский П.В. , Зубавичус Я.B. , Байдакова M.B. , Иванькова E.M. , Мясникова Л.П.
Published: May 2019

With the help of small angle X-ray diffraction using synchrotron X-ray beamline"Belok" in NRC «Kurchatov Institute» was shown that the first order sold phase transition in the tetracosane C24H50 develops by a heterogeneous mechanism in a very narrow thermal interval (delta ≈0,1K ) in accordance with the theory of diffuse phase transition.
The work was financially supported by the Presidium RAN Program №32 "Nanostructures: physics, chemistry, biology, basics of technology" and Russian Foundation of Basic Research (project 16-03-00493А) using beamline "Belok" in NRC
Углеродные наноструктуры на полупроводниковой подложке
Authors: Давыдов С.Ю.
Published: May 2019

AbstractThe analytical expressions for the density of states and the occupation numbers are obtained for simple models of carbon nanostructures (graphene–boron nitride lateral heterostructure, decorated zigzag edges of semi-infinity graphene and graphene nanoribbons, and decorated carbyne). The main attention is placed to the strong-coupling regime of the nanostructures with a semiconducting substrate. The numerical estimations are given for the SiC substrate.
Уравновешенные концентраторы потока и их применение для снижения электромагнитных сил в магнитных системах
Authors: Шнеерсон Г.А. , Дегтев Д.А.
Published: May 2019

AbstractMagnetic flux concentrators, viz., bodies with radial cuts introduced into the field of a magnet, substantially affect the magnitude and distribution of electromagnetic forces in magnetic systems. The fields of magnetic systems with flux concentrators are calculated in the perfect conduction approximation, which is valid in the case of a clearly pronounced skin effect. The possibility of complete or partial compensation of forces acting on the concentrator is demonstrated for some model problems. At the same time, it is shown that the placement of the concentrator near the winding of the magnet can reduce the forces acting on the winding. Therefore, the concentrator unloads the winding, remaining balanced completely or partly. As a result, the requirements of devices ensuring the durability of the magnetic system are substantially reduced.
Разрядная система с самонакаливаемым полым катодом и испаряемым анодом в остроугольном магнитном поле для нанесения оксидных покрытий
Authors: Гаврилов Н.В. , Каменецких А.С. , Емлин Д.Р. , Третников П.В. , Чукин А.В.
Published: May 2019

AbstractThe properties of a discharge with a self-heated hollow cathode and an evaporating anode placed in a cusp magnetic field created by two oppositely connected coils installed near the anode and cathode are studied. There is a negatively biased sample holder in the region of the annular magnetic slit. Compressing the discharge column at the anode with a magnetic field ensures effective evaporation of the metal (aluminum) loaded into the crucible anode; the density of the oxygen-containing plasma generated in the volume was controlled by changing the current of the cathode magnetic coil. The rate of depositing the aluminum oxide coating by reactive anodic evaporation, in contrast to reactive magnetron sputtering, is not limited by the oxidation of the sputtering target; the lifetime of the thermal emission cathode is hundreds of hours. The high ion-current density of the plasma (up to 10 mA/cm^2) ensures a decrease in the crystallization temperature and the formation of nanocrystalline oxide coatings. The conditions are determined for a stable discharge operation with a current of up to 40 A at a pressure of 0.1 Pa in an oxygen-argon mixture. The results of probe diagnostics of the plasma discharge parameters, deposition rate measurements, and an analysis of the structure and properties of aluminum oxide coatings are given.
Возможность использования отрицательной спиновой компоненты в нейтронных поляризующих устройствах. Первые результаты
Authors: Гордеев Г.П. , Забенкин В.Н. , Диденко Г.П. , Аксельрод Л.А. , Лазебник И.М. , Лямкин В.А.
Published: May 2019

The results of experimental verification of the possibility of increasing the neutron beams luminosity of polarizing devices based on magnetized supermirrors are presented. The essence of the experiment is to use both components of the neutron spins in the beam. The positive component is reflected from one magnetized mirror, and the passing mirror opposite component after turning 180 degree is reflected from another similar mirror. Both beams were recorded with one detector. Taking into account the reflection coefficients of the components by the mirrors and the efficiency of the rotation of the opposite component, an increase in the neutron intensity was obtained approximately twice with an average polarization of about 66%. The experiments were performed on a monochromatic neutron beam.
Исследование неоднородности электрохимического электрода со смешанной проводимостью
Authors: Нечитайлов А.А. , Глебова Н.В. , Томасов А.А. , Краснова А.О. , Зеленина Н.К.
Published: May 2019

AbstractThe ionic resistance of membrane–electrode assemblies of oxygen–hydrogen fuel cell electrodes containing platinum nanoparticles on carbon black, carbon nanofibers, and proton-conducting Nafion polymer in a wide range of compositions (10–80 wt %) are studied in situ by the methods of current–voltage characteristics, electrochemical impedance spectroscopy, and simulation of the impedance hodograph. Conditions that make it possible to correctly determine the ionic resistance of the electrode on the basis of an analysis of the linear approximation of the high-frequency region of the impedance hodograph are found. It is shown that the occurrence of inhomogeneities and an anomalous increase in the ionic resistance with an increase in the content of Nafion in the electrode are associated with a decrease in the volume fraction of water-generation centers (particles of electrochemically active platinum), which leads to incomplete wetting of Nafion.
Эффект совместного влияния малых добавок углеродных наночастиц различной морфлогии на механические характеристики сшитых полиуретанов при статических и динамических нагрузках
Authors: Гаркушин Г.В. , Разоренов С.В. , Тарасов А.Е. , Анохин Д.В. , Бадамшина Э.Р.
Published: May 2019

AbstractInfluence of small additives of fullerene, graphene oxide, and their combinations in the ratio of 85 : 15 on the structure and mechanical properties of cross-linked polyurethanes under static and dynamic loads has been investigated. Nanocomposite structures have been studied by X-ray diffraction analysis and scanning electron microscopy. It is shown that the presence of carbon nanoparticles in the composite reduces its strength under both static and shock-wave loads. The synergistic effect of the mixture of carbon nanoparticles manifests itself as an increase in the elastic modulus by a factor of 1.25 in comparison with the initial polymer.
Сдвиг и уширение циркулярных состояний атома тепловым излучением
Authors: Каменский А.А. , Овсянников В.Д. , Глухов И.Л.
Published: May 2019

Analytical expressions for spontaneous and induced by blackbody radiation energy shifts and widths of atomic circular states are derived. The features of asymptotic behavior of the total width and energy shifts for highly excited Rydberg circular states in blackbody radiation field are described. Approximate equations are proposed for simple evaluations of energy characteristics and an absence of temperature-independent spontaneous contribution to the total energy width in a range of high temperatures and principal quantum numbers is demonstrated.
Внутридопплеровские резонансы, обусловленные осцилляциями Раби на атомных переходах в тонких газовых ячейках
Authors: Измайлов А.Ч.
Published: May 2019

Theoretical research is carried out of excitation of atoms from the ground quantum level to a metastable state by the running monochromatic radiation in thin gas cell, whose inner thickness is much less than its radius. As a result, sub-Doppler resonances has been discovered and analyzed, which appear in the population of the metastable atomic level at scan of the radiation frequency because of light induced Rabi oscillation on the given optical transition and also transit relaxation of atoms in the considered cell with the rarefied gas. Such nontrivial resonances may be detected in atomic fluorescence by additional probe light beam. The method for direct measurement of the Rabi frequency on spectral intervals between established sub-Doppler resonances is proposed. Obtained results may be applied in atomic spectroscopy for precise determination of components of matrix elements of dipole moments and related Einstein coefficients and oscillator strengths of quantum transitions between ground and metastable atomic levels.
Нанокомпозиционный оптосенсор ионов свинца в воде
Authors: Денисюк И.Ю. , Игнатьева Ю.А. , Успенская М.В. , Фокина М.И.
Published: May 2019

AbstractSpectral dependences of complexation in the system of the xylenol orange dye that was immobilized on the surface of ZnO nanoparticles introduced into the volume of hydrogel and lead ions Pb^2+ have been investigated. It has been shown that the deposition of the dye on the ZnO nanoparticles leads to its binding on the surface and absence of its washing out from the hydrogel, but this process does not prevent the formation of the complexes of the dye with lead ions, which is characterized by increased absorption in the region of 580 nm. The film nanocomposite can be used as a sensor due to its high sensitivity to the presence of low lead concentrations.
Анализ изотопического состава выдыхаемого воздуха методами диодной лазерной спектроскопии в районе 2 μm для диагностики Helicobacter pylori-ассоциированных заболеваний-=SUP=-*-=/SUP=-
Authors: Ивашкин В.Т. , Касоев С.Г. , Степанов Е.В.
Published: May 2019

Spectral analysis of 13СО2/12СО2 isotope ratio in exhaled air based on tunable diode laser spec-troscopy was applied for diagnostics of digestive organ diseases associated with Helicobacter pylori infection. Special spectrophotometer based on tunable diode laser was developed for the analysis of breath isotope content. Spectral range near 2.05 microns where the rotational-vibration R-branch of the 20013-00001 band of 12CO2 interferes with the P-branch of the 20012-00001 band of 13CO2 was used. The 13C-Urea Breath Test (13C-UDT) was used for the H. pylori infection diagnostic in gastrointestinal tract of 309 tested persons. The results of the isotope breath test were compared with the data of morphological analysis of gastric and duodenal mu-cosa obtained by fibrogastroduodenoscopia. For the first time the total value of the histology analysis results for biopsy material taken in the stomach body, in the distal part of stomach and in the duodenum was proposed to be used for the comparative analysis with 13C-UBT data. A relationship of 13C-UBT data with age, nosology, activity and severity of inflammation process, atrophy degree, and type of eradication therapy was analyzed. Distribution of 13C-UBT data ob-tained before and after therapy was demonstrated to reflect epidemiology of gastroduodenal dis-eases, H.pylori infection incidence, specifics of gastrointestinal tract colonization by H.pylori, parameters of inflammation process, as well as therapy effectiveness and peculiarity of the in-fection restoration at failed eradication therapy.
Solid lipid curcumin-loaded particles for in vivo fluorescent imaging in humans: a proof of concept-=SUP=-*-=/SUP=-
Authors: Gogoleva M.A. , Yakimov B.P. , Rodionov S.A. , Tikhonova T.N. , Gurfinkel Y.I. , Fadeev V.V. , Lademann J. , Darvin M.E. , Shirshin E.A.
Published: May 2019

The possibility to use oral intake of fluorescent dyes approved on humans for intravital fluorescence in vivo imaging is attractive due to its simplicity and non-invasive character. Here we investigate the potential of solid lipid curcumin particles (SLCP) for imaging of capillary permeability using fluorescence video capillaroscopy. Curcumin fluorescence corresponding to 0.7 μg/ml concentration was observed from blood plasma after oral consumption of 2 g of SLCP. However, this signal was ~ 15% higher than that of blood plasma intrinsic fluorescence, which was itself at least 10-fold lower than the background signal from pericapillary tissue. By comparing the optical properties and concentration to the case of intravenous injection of sodium fluorescein, we analyzed which parameters of the experiment should be optimized for using oral consumption of fluorescing compounds in intravital in vivo capillaroscopy measurements.
Исследование нейроваскулярных структур с помощью фазово-модуляционной спектрофотометрии-=SUP=-*-=/SUP=-
Authors: Сафонова Л.П. , Орлова В.Г. , Шкарубо А.Н.
Published: May 2019

The possibility of using phase modulation spectrophotometry for the detection and recognition of large blood vessels and nerves in the biological tissues volume in the tasks of neurosurgery with endoscopic endonasal access while removing the skull base tumors has been investigated. Optical and dynamic characteristics of various neurovascular structures types were studied. Informative independent parameters and their corresponding criteria for the detection and recognition of neurovascular structures in the tissue volume, based on the difference in the optical properties of the blood, nerves and their surrounding tissues, was proposed and experimentally investigated in vivo and in situ. The obtained preliminary results indicate the promise of applying the method of phase modulation spectrophotometry in endoscopic neurosurgery and can be used in spectrophotometry with the impulse time-domain approach.
Измерение поляризации света при зеркальном и диффузном отражении от растительного покрова
Authors: Азизов Б.М. , Мехтиев Д.С. , Кулиева С.Г.
Published: May 2019

In this article mirror and diffuse reflection of light from wheat leaves at two vegetative stages of its development are considered. The research results can serve as a methodological basis for the development of models of optical properties and other crops.
Особенности обобщенной синхронизации в системах с запаздыванием
Authors: Плотникова А.Д. , Москаленко О.И.
Published: May 2019

Peculiarities of the generalized synchronization regime in unidirectionally coupled time-delayed generators are studied. Four different cases of interaction between systems characterized by different number of positive Lyapunov exponents are considered. The thresholds of the generalized synchronization regime onset is found to depend sufficiently on the degree of chaotic states of interacting systems, whereas the coupling between systems characterized by different number of positive Lyapunov exponents results in appearance of additional synchronous fields.
Соотношения взаимности для нелинейных систем
Authors: Игнатьев В.К.
Published: May 2019

The quantum proof of the reciprocal relations for nonlinear non-stationary systems in a magnetic field is obtain in the approach of Markov’s relaxation.
Высокочастотные рельефно-фазовые голографические решетки на обработанном коротковолновым УФ-излучением бихромированном желатине
Authors: Ганжерли Н.М. , Гуляев С.Н. , Маурер И.А. , Хазвалиева Д.Р.
Published: May 2019

For the first time, the possibility of creating relief-phase holographic gratings with a high spatial frequency of 1500 mm-1 on dichromate gelatin (DCG) layers using the destructive effect of short-wave UV radiation on gelatin is shown.
Новый способ обработки изображений, полученных шлирен-методом с фоновым экраном
Authors: Баринов Ю.А.
Published: May 2019

Testing of the Background Oriented Schlieren technique was performed. Нot air flow with known temperature was used as an object. It was found that the technique may give an incorrect result on objects of millimeter size. It was found that the error occurs when using standard software. Another processing method and its software implementation are proposed.