bluuebunny/crossref_metadata_2025 huggingface dataset:
Fishery and geospatial mapping of pelagic elasmobranchs from mechanised gillnetters of Tharuvaikulam, Thoothukudi, south-east coast of India
Authors: Manojkumar P.P. , Ranjith L. , Kanthan K.P.
Published: April 2019

The pelagic elasmobranchs fishery of multiday gillnetters (MGNs) of Tharuvaikulam, Thoothukudi was studied during 2015-2016. Fishery data revealed that MGNs targeting scombrids and other large pelagic fishes also contribute to the pelagic elasmobranch landings accounting for 7.67 and 5.3% of total elasmobranchs landed at Tharuvaikulam during 2015 and 2016 respectively. The catch per unit effort (CPUE) varied from 2.09 to 175 kg (2015) and 13 to 124.95 kg (2016). In total, 15 species of pelagic elasmobranchs were recorded during the study period, which includes 7 species of sharks and 8 species of rays. The pelagic elasmobranchs fishery of Tharuvaikulam depends mainly on two species namely bigeye thresher, Alopias superciliosus and spinetail devilray, Mobula japanica. The geospatial mapping revealed that fishing grounds of MGNs was between 77° to 80°E longitudes and 7° to 9° N latitudes with depth ranging from 50 to 200 m. The persistence of fishing grounds of pelagic elasmobranchs was identified by classifying the fishing areas of Gulf of Mannar Biosphere Reserve (GOMBR) into seven zones. The results showed that more fishing happens in Zone 4, off Thoothukudi between 78° to 79°E and 8° to 9°N followed by Zone 7, off Kanyakumari between 77° to 78°E and 7° to 8°N. Seasonal analysis revealed that along with the targeted groups, the CPUE of pelagic elasmobranchs was higher during the pre-monsoon season. The present paper illustrates the zonal distribution of pelagic elasmobranchs in the fishing grounds of MGNs in GOMBR, along the south-east coast of India and the results of the study would serve as baseline information for formulating future management plans.
Kajian Etnosains Madura dalam Proses Produksi Garam sebagai Media Pembelajaran IPA Terpadu
Authors: Hadi Wiwin Puspita , Ahied Mochammad
Published: April 2019

Penelitian ini bertujuan untuk merekronstruksi pengetahuan asli masyarakat dalm proses produksi garam ke dalam pengetahuan ilmiah yang dijadikans sebagai media pembelajaran IPA Pengambilan data dilakukan di desa Padelegan dan desa Bunder Kecamatan Pademawu kabupaten Pamekasan.Metode penelitian yang dilakukan adalah kualitatif deskriptif dengan teknik pengambilan data melalui observasi, angket dan wawancara. Data yang diperoleh kemudian dianalisis, diverifikasi, dan direduksi kemudian dikontruski ke pengetahuan ilmiah dan diintepretasikan ke konsep sains yang ada di pembelajaran IPA. Hasil penelitian menunjukkan bahwa proses pembuatan garam yang dilakukan masyarakat dapat diinterpretasikan ke dalam pengetahuan sains dan diimplementasikan dalam pembelajaran IPA

Kata Kunci: etnosains, garam, pembelajaran IPA.

 

ABSTRACT

This study was aimed to reconstruct science society into scientific knowledge in the production process of salt for learning material that was conducted salt farmers in Padelegan and Bunder Village, Pemekasan Regency, East Java Indonesia. The method of this study was qualitative descriptive with retrieval of data through direct observation, questionnaries, and interviews. The obtained data were analyze, veryfied, reduced and reconstruction into scientific knowledge and were interpreted. The focus of this study was tradition of salt process especially on knowledge of salt farmer about raw materials salt and crystalization of salt. The result showed that were five indigenous science from the salt production which could be recontructed into scientific knowledge.

Keywords: ethnoscience, salt, science learning.
Prenatal diagnosis of congenital intracranial teratoma
Authors: A.E. Volkov , V.V. Voloshin , O.A. Fomenko
Published: April 2019

The case of prenatal ultrasound diagnosis of congenital brain teratoma at 35 weeks 4 days of gestation is
presented. At ultrasound examination no pathology was detected at 12, 21 and 31 weeks of gestation. During
ultrasound scanning of the fetus at 35 weeks of gestation the following changes were revealed: the brain architecture is represented by a thinned cortex, inhomogeneous cystic solid formation, significant macrocephaly
and hydrocephaly. Pregnancy is ended by сaesarean section. A liveborn fetus with significant macrocephaly is
extracted. He died after 2 days after birth. The tumor is estimated as a congenital immature (malignant) teratoma
of the brain accordance with histological examination.
Prenatal ultrasound observation of duplication of the large intestine wall
with the formation of cysts
Authors: I.I. Ryabov
Published: April 2019

The article presents the results of prenatal ultrasound monitoring of a rare colon anomaly — duplication of
a blind gut wall with cyst formation. This abnormality was difficult to accurately in during prenatal and postnatal
periods using sonography, computer tomography and magnetic resonance imaging. The final diagnosis made
only after histopathological examination of gross specimen obtained in operation.
Prenatal ultrasound diagnosis of a rare case of hypospadias scrotal form
with papillomatosis of the posterior urethra
Authors: M.V. Kubrina , N.V. Schapov , T.N. Melnik et all
Published: April 2019

A case of prenatal ultrasound diagnosis of hypospadias, scrotal form with papillomatosis of the posterior
urethra at 36 weeks of gestation is presented. Only the scrotal form of hypospadias was detected prenatally. The
formation, which localized between the split of scrotum and proceeded from the posterior urethra, had a papillomatous structure. The neoplastic process of this mass was excluded. The diagnosis was made in postnatal period
with the help of additional research methods: newborn karyotype, neonatal screening for adrenogenital syndrome,
diagnostic cystoureterography, histological examination and immunohistochemical analysis of tumor formation. The pathology of the external genitalia was isolated. No changes in the newborn's karyotype were detected.
Preparation of Carbon-14 Labeled 2-(2-mercaptoacetamido)-3-phenylpropanoic Acid as Metallo-beta-lactamases Inhibitor (MBLI), for Coadministration with Beta-lactam Antibiotics
Authors: Maleki Ali , Taheri-Ledari Reza , Eivazzadeh-Keihan Reza , de la Guardia Miguel , Mokhtarzadeh Ahad
Published: April 2019

Aim and Objective:

Bacteria could become resistant to β-lactam antibiotics through production of β-
lactamase enzymes like metallo-β-lactamase. 2-(2-mercaptoacetamido)-3-phenylpropanoic acid was reported
as a model inhibitor for this enzyme. In order to elucidate the mechanism of action in the body’s internal
environment, preparation of a labeled version of 2-(2-mercaptoacetamido)-3-phenylpropanoic acid finds
importance. In this regard, we report a convenient synthetic pathway for preparation of carbon-14 labeled 2-(2-
mercaptoacetamido)-3-phenylpropanoic acid.

Materials and Methods:

This study was initiated by using non-radioactive materials. Then, necessary
characterization was performed after each of the reactions. Finally, the synthesis steps were continued to
produce the target labeled product. For labeled products, the process was started from benzoic acid-[carboxyl-
14C] which has been prepared from barium 14C-carbonate. Chromatography column and NMR spectroscopy
were used for purifications and identification of desired products, respectively. Barium [14C]carbonate was
purchased from Amersham Pharmacia Biotech and was converted to [14C]benzyl bromide. Radioactivity was
determined using liquid scintillation spectrometer.

Results:

We used [14C]PhCH2Br which was previously prepared from [14C]BaCO3, H2SO4, PhMgI, LAH and
HBr, respectively. To neutralize the [14C]phenylalanine in acidic condition and to reach an isoelectric point of
phenylalanine (pH = 5.48), Pb(OH)2 was used. Next, thioacetic acid and bromo acetic acid were used to
prepare (acetylthio) acetic acid. A peptide coupling reagent was used in this stage to facilitating amide bond
formation reaction between [14C]methyl-2-amino-3-phenyl propanoate hydrochloride and (acetylthio) acetic
acid.

Conclusion:

Carbon-14 labeled 2-(2-mercaptoacetamido)-3-phenylpropanoic acid via radioactive
phenylalanine was obtained with overall chemical yield 73% and radioactivity 65.3 nCi. The labeled target
product will be used for in vivo pharmacological studies.
Ultrasonic Echolocation Device for Assisting the Visually Impaired
Authors: Mick Ben , Reddmann Nathan , Manwar Rayyan , Avanaki Kamran
Published: April 2019

Background:

Echolocation is a technique whereby the location of objects is determined via reflected sound. Currently, some visually impaired individuals use a form of echolocation to locate objects and to orient themselves. However, this method takes years of practice to accurately utilize.

Aims:

This paper presents the development of a sensory substitution device for visually impaired users, which gauged distances and the placement of objects.

Methods:

Using ultrasonic technology, the device employed a method of echolocation to increase the user's independence and mobility. The main components of this device are an ultrasound transceiver and a miniaturized Arduino board. Through research and prototyping, this technology was integrated into a biomedical application in a watch form factor which provides feedback to the user regarding the measured distance by the ultrasonic transducer.

Results:

The output of this process is a tactile feedback that varies in intensity proportional to the distance of the detected object. We tested the device in different scenarios including different distances from a different material. The difference between the device reading and the actual distance, from 0 to 400 cm was statistically insignificant.

Conclusion:

It is believed this device will boost the confidence of the user in navigation.
Anti-inflammatory Plant Polyphenolics and Cellular Action Mechanisms
Authors: Mir Reyaz H. , Masoodi Mubashir H.
Published: April 2019

Background:

Polyphenolics, a group of natural substances with a wide distribution in the
plant kingdom present a great diversity of biological activities such as anti-oxidative, anti-inflammatory,
anti-mutagenic, anti-carcinogenic, modulation of enzyme activity, prevention of CHD, etc. The objective
of this review was to describe the relevant aspects of polyphenolics, reporting the different known
groups, the probable mechanisms by which they act as anti-inflammatory agents. An attempt was also
made to enumerate the possible leads e.g. curcumin, resveratrol, baicalein for further development.

Methods:

For peer-reviewed research literature we undertook a structured search of bibliographic databases
using a focused review question. The quality of retrieved papers was appraised using standard
tools. The systemic review consists of research using scientific databases such as PubMed, Scopus,
Science Direct, and Google Scholar.

Research:

Compounds like Quercetin, luteolin, apigenin, fisetin, wogonin, and baicalein showed antiinflammatory
activity in-vitro through different cellular mechanisms and these were also reported to
possess significant anti-inflammatory activity in animal models of inflammation.

Conclusion:

It is evident that polyphenolic compounds such as flavonoids, lignans, phloroglucinols,
stilbenes, diarylheptanoids, quinones, and phenylpropanoids exhibited significant anti-inflammatory
activity in-vivo as well as in-vitro. Although, these active compounds are not drugs per se, however,
they deserve further investigation as potential candidates for anti-inflammatory drug development
through preclinical and clinical studies.
A Hybrid Combination of LS-SVM and KPCA with Bat Algorithm for Intrusion Detection
Authors: V. Thiruppathy Kesavan , K. Loheswaran
Published: April 2019

Background:

Intrusion Detection System refers to a kind of software which is designed for securing
a network or an information system by alerting the administrators automatically when someone is
trying to compromise the overall system through malicious activities. An intrusion is a process of causing a
system to enter into an insecure state. Thus, an intruder is a person or an attacker who attempts to violate the
security measures by interrupting the integrity and confidentiality of a system.

Objective:

Today, security threads are becoming big issues when working with high speed network connections,
one solution is the intrusion detection system which promises to provide network security. This paper proposed
Least Square Support Vector Machine (LS-SVM) based on Bat Algorithm (BA) for intrusion detection.

Methods:

The proposed techniques have divided into two phases. In the first phase, KPCA is utilized as a
preprocessing of LS-SVM to decrease the dimension of feature vectors and abbreviate preparing time with a
specific end goal to decrease the noise caused by feature contrasts and enhance the implementation of LSSVM.
In the second phase, least square support vector machine with a BA is applied for the classification of
detection. BA utilizes programmed zooming to adjust investigation and abuse amid the hunting procedure.
Finally, as per the ideal feature subset, the feature weights and the parameters of LS-SVM are optimized at
the same time.

Results:

The proposed algorithm named is Kernel principal component analysis based least square support
vector machine with bat algorithm (KPCA-BA-LS-SVM). To show the adequacy of proposed method, the
tests are completed on KDD 99 dataset which is viewed as an accepted benchmark for assessing the execution
of intrusions detection. Furthermore, our proposed hybridization method gets a sensible execution regarding
precision and efficiency.

Conclusion:

A BA model with a novel hybrid KPCA-LS-SVM was proposed in this paper for intrusion detection
system. The parameters for LS-SVM classifier are chosen with the usage of BA, the necessary features
of intrusion detection data was separated using KPCA and the multi-layer SVM classifier. This classifier
checks whether any activity encounters an attack. The N-RBF supports the Gaussian kernel work by
measuring the preparation time and forwarding the LS-SVM classifiers execution. As future work, several
algorithms should be developed by combing other available classification methods with kernel systems resulting
in efficient planning of examination and online intrusion detection.
Diversidad, fluctuación poblacional y hospedantes de moscas de la fruta Anastrepha spp. y Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) en el valle de Abancay, Apurímac, Perú
Authors: Ramos-Peña Alvaro Manuel , Yábar-Landa Erick , Ramos-Peña Julio Cesar
Published: April 2019

El objetivo del presente trabajo fue identificar las especies de moscas de la fruta, determinar su fluctuación poblacional y sus hospedantes en el Valle de Abancay, Apurímac. Se instalaron 14 trampas Multilure, con Buminal® al 4% como atrayente alimenticio, renovado semanalmente entre octubre del 2014 a septiembre del 2015. Los insectos capturados fueron colocados en frascos con alcohol al 70% y enviados al Laboratorio de Entomología C-333 de la UNSAAC para su posterior identificación. Se contabilizó tanto las hembras y machos, y la fluctuación poblacional se estableció con base en el índice de moscas/trampa/día (MTD) para especies de Anastrepha y Ceratitis capitata (Wiedemann). Estos datos se relacionaron con datos de temperatura, precipitación y disponibilidad de hospedantes. Se colectaron frutos una vez por mes de potenciales hospedantes de distintos campos de producción para recuperar tefrítidos adultos en cajas de maduración con sustrato de arena. Se colectaron un total de 21,974 individuos. Se identificaron diez especies: A. fraterculus (Wiedemann), A. distincta Greene, A. serpentina (Wiedemann), A. schultzi Blanchard, A. manihoti Lima, A. chiclayae Greene, Anastrepha sp. 1, A. pickeli Lima, A. atrox (Aldrich) y Ceratitis capitata (Wiedemann). Las especies con mayor población fueron A. fraterculus, A. distincta y C. capitata. Las mayores poblaciones se presentan en los meses de diciembre a mayo. La disponibilidad de hospedantes es el factor que mejor explica la fluctuación poblacional de Anastrepha fraterculus, A. distincta, A. manihoti y la población total de moscas de la fruta. Se identificaron un total de 16 especies hospedantes. Citrus x aurantium L. (Rutaceae), Annona cherimola Mill. (Annonaceae) y Psidium guajava L. (Myrtaceae) fueron los frutos con mayores índices de infestación con 125.7, 101.63 y 87.5 pupas.kg-1, respectivamente.
XVI Международная конференция "Термоэлектрики и их применения --- 2018" (ISCTA 2018), Санкт-Петербург, 8-12 октября 2018 г. Термоэлектрические свойства лент In-=SUB=-0.2-=/SUB=-Ce-=SUB=-0.1-=/SUB=-Co-=SUB=-4-=/SUB=-Sb-=SUB=-12.3-=/SUB=-, полученных методом быстрой закалки
Authors: Новиков С.В. , Бурков А.Т. , Танг Х. , Ян Я. , Орехов А.С.
Published: April 2019

The article presents experimental results on thermoelectric properties of In0.2Ce0.1Co4Sb12.3 alloy, prepared by rapid quenching technique. The initial material, typically in the form of thin ribbons, has quasi-amorphous structure. Usually, the ribbons are crashed to powder with subsequent compaction by hot-pressing or spark plasma sintering techniques. However, the thermoelectric properties of as-prepared ribbons have been unknown. In this work the thermopower and the electrical resistivity of In0.2Ce0.1Co4Sb12.3 ribbons are studied for the first time at temperatures from 100 K to 750 K. Temperature stability range of the quasi-amorphous structure, and the crystallization kinetics were investigated.
Термоэдс тонких пленок Bi-=SUB=-1-x-=/SUB=-Sb-=SUB=-x-=/SUB=- (0≤ x≤0.15) на подложках из слюды и полиимида в температурном интервале 77-300 K
Authors: Суслов М.В. , Грабов В.М. , Комаров В.А. , Демидов Е.В. , Сенкевич С.В. , Суслов А.В.
Published: April 2019

This report presents the results of the study of thermoelectricpower of the thin block films of Bi1−xSbx (0 ≤ x ≤ 0.15)
with the thickness of 100−1000 nm on the mica and polyimide
substrates in the temperature range 77−300 K. The applied
technique for measuring thermoelectric power allows to prevent
the additional film deformation due to the difference in the thermal
expansion of the sample in question and measurement cell. The
structure, temperature dependences of the thermopower and the
resistivity of thin films were analyzed, and the power factor was
estimated. A difference was found in the nature of the temperature
dependences of the thermopower and the specific resistance
of films on mica and polyimide substrates. This difference is
explained by the change of the band structure parameters under the
influence of film deformation due to the difference in the thermal
expansion of the film and substrate.
Эффекты Холла и Зеебека в тонких пленках висмута на подложке из слюды в диапазоне температур 77-300 K
Authors: Комаров В.А. , Грабов В.М. , Суслов А.В. , Каблукова Н.С. , Суслов М.В.
Published: April 2019

AbstractThe effects of film thickness and block size on the Hall and Seebeck effects in bismuth films on mica substrates are analyzed using experimental data. A preferential decrease in the electron contribution with a decrease in the film thickness and a preferential decrease in the hole contribution with a decrease in the block size are established. The Hall and Seebeck coefficients are calculated using the classical size effect with regard to carrier scattering at block boundaries and anisotropy of the properties of carriers. In the calculation, the electron and hole mobility components and their concentration in a bismuth single crystal are used and the crystallographic orientation of the film crystal are taken into account. The results of the calculation are in good agreement with the experimental data. It is concluded that the value and sign of the Hall and Seebeck coefficients in bismuth films are determined by the competition of the classical size effect and scattering at block boundaries.
Параметры зонной структуры тонких пленок Bi-=SUB=-1-x-=/SUB=-Sb-=SUB=-x-=/SUB=- (0≤ x≤ 0.15) на подложках с различным температурным расширением
Authors: Суслов А.В. , Грабов В.М. , Комаров В.А. , Демидов Е.В. , Сенкевич С.В. , Суслов М.В.
Published: April 2019

The report presents the positions of the conductance
and valence band extremes in relation to the chemical potential
of the thin bismuth–antimony films (from 0 to 15 at% Sb) on
substrates with different thermal expansion. The results are based
on the galvanomagnetic properties study of thermal deposited
thin films. A significant increase in the concentration of charge
carriers in films on substrates with a large thermal expansion
was found. The results of calculating the valence band and the
conduction band positions at 77 K, depending on the thermal
expansion coefficient of the substrate used, are presented. The
thin films plane deformation caused by the difference in the film
and substrate materials thermal expansion leads to a change in the
positions of the conduction band and the valence band of the films
relative to their positions in a single crystal with corresponding
composition
Влияние лантана на транспортные свойства оксиселенидов Bi-=SUB=-1-x-=/SUB=-La-=SUB=-x-=/SUB=-CuSeO
Authors: Панкратова Д.С. , Новицкий А.П. , Кусков К.В. , Сергиенко И.А. , Лейбо Д.В. , Бурков А.Т. , Константинов П.П. , Ховайло В.В.
Published: April 2019

In this work we present the results of the transport properties study for p-type Bi1-xLaxCuSeO (x = 0.02; 0.04; 0.06) oxyselenides. Accordingly to temperature dependencies of the electrical resistivity, charge carriers concentration and mobility, it was revealed that the substitution of Bi3+ ions to La3+ ions leads to charge carriers concentration enhancement caused by generation of holes, which is presumably attributed to the bismuth deficiencies formation with respect to the substitution level.

The work was carried out with financial support from the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST “MISIS”.
Безразмерная математическая модель термоэлектрического охладителя: режим Delta T-=SUB=-max-=/SUB=-
Authors: Мельников А.А. , Тарасов О.М. , Чеков А.В. , Башкин М.А.
Published: April 2019

AbstractThe thermal resistances on the cold and hot sides substantially affect the output characteristics of thermoelectric devices. A dimensionless mathematical model of a thermoelectric cooler, which makes it possible to calculate device parameters, such as the optimal thermal resistance ratio on the cold and hot sides as well as the optimal current taking into account the influence of thermal resistances, is presented. The maximal temperature difference Δ T _max mode is considered. It is shown that the optimal cooler parameters are different for implementation of the Δ T _max and Q _max modes. The determining factor for the Δ T _max mode is the influence of the thermal resistance on the hot side, and the optimal current is 0.4–0.7 of the maximal current in most cases for the material with ZT = 1. It is shown that an additional increase in Δ T _max of a cooler is attained with a decrease in the thermal conductivity of the thermoelectric material due to a decrease in the influence of the thermal resistance on the hot side besides the effect from an increase in ZT . An increase in the length of thermoelectric legs has the same positive effect of an increase in Δ T _max of a cooler, while a decrease in the leg length negatively affects Δ T _max.
Изменение состояния примесных атомов -=SUP=-119m-=/SUP=-Sn в PbTe в процессе установления радиоактивного равновесия изотопов -=SUP=-119m-=/SUP=-Te/-=SUP=-119-=/SUP=-Sb
Authors: Серегин П.П. , Марченко А.В. , Насрединов Ф.С. , Жаркой А.Б.
Published: April 2019

AbstractThe parameters of the emission Mössbauer spectra of PbTe using the ^119 m Sn daughter isotope with different parent nuclei ^119 mm Sn, ^119Sb, and ^119 m Te are compared. This comparison makes it possible to identify impurity tin atoms in both lead-telluride sublattices. It is found that the ratio of tin concentrations in different sublattices depends on the time after source preparation.
Термоэлектрические свойства нанокомпозитов Sb-=SUB=-2-=/SUB=-Te-=SUB=-3-=/SUB=- c графитом
Authors: Кульбачинский В.А. , Кытин В.Г. , Зиновьев Д.А. , Маслов Н.В. , Singha P. , Das S. , Banerjee A.
Published: April 2019

AbstractAntimony-telluride-based nanocomposite samples containing different weight fractions of graphite (Sb_2Te_3 + x % graphite, where x = 0.0, 0.5, 1.0, and 2.5%) are synthesized and studied. The samples are produced by a solid-state reaction with the use of a ball mill. X-ray diffraction measurements show that the Sb_2Te_3 phase is present in the nanocomposites. All of the diffraction peaks are identified as corresponding to the rhombohedral structure of symmetry $$R\bar {3}m$$ . No additional peaks related to graphite are observed because of its low content. Moreover, the X-ray data show the insolubility of graphite in Sb_2Te_3: the peaks related to Sb_2Te_3 remain unchanged upon the addition of graphite. The thermal conductivity, thermoelectric power, and resistivity of the samples are studied in the temperature range 80 K ≤ T ≤ 320 K. The thermal conductivity k of the nanocomposite decreases several times compared to the thermal conductivity of single-crystal Sb_2Te_3 and reaches k ≈ 0.95 W m^–1 K^–1 at x = 0.5%. The parameter k unsteadily depends on the content of graphite. The thermoelectric power of the nanocomposites with graphite at x = 1.0% is higher compared to that of nanostructured Sb_2Te_3.
Термоэдс латтинжеровской жидкости
Authors: Иванов Ю.В. , Урюпин О.Н.
Published: April 2019

The thermopower of a Luttinger liquid with a potential barrier is calculated. The long-range nature of the electron-electron interaction is taken into account. It is shown that an increase of the interaction range qualitatively changes the temperature dependence of the thermopower. At low temperatures, the Seebeck coefficient of the Luttinger liquid is significantly less than the corresponding coefficient of a one-dimensional Fermi gas. With increasing temperature, the thermopower increases rapidly and may exceed that of the Fermi gas. The results obtained are in qualitative agreement with experimental data for quasi-one-dimensional 5-nm-thick InSb wires.
Холодильный коэффициент составной охлаждающей термоэлектрической ветви
Authors: Драбкин И.А.
Published: April 2019

AbstractOne of the main energy characteristics of a cooling leg is the maximum available temperature difference (Δ T _max). Its increase indicates an increase in the coefficient of performance (COP) at all temperatures. The use of a segmented leg makes it possible to increase the Δ T _max value; however, the maximum available COP increases only at large temperature differences, whereas at small temperature differences the maximum available COP is even smaller than in a simple leg.
Эффективные кристаллы Bi-Sb для термоэлектрического охлаждения при температурах T≲180 K
Authors: Сидоренко Н.А. , Дашевский З.М.
Published: April 2019

Methods of extrusion are widely used in technology of thermoelectric (TE) materials manufacturing with high strength and good TE properties at temperatures above 200 K. The method of extrusion of Bi - Sb single crystals in the liquid environment under high hydrostatic pressure is considered. The construction of experimental equipment is presented. It was shown that presented method of extrusion allows preparing of polycrystalline material with high TE and improved strength properties at temperatures below 180 K.
Об оценках электронного сродства политипов карбида кремния и разрывов зон в гетеропереходах на их основе
Authors: Давыдов С.Ю.
Published: April 2019

AbstractTwo different procedures for estimating the electron affinity of SiC polytypes and the interrelation of these procedures with the results of ab initio calculations are discussed. Simple corrections to the Shockley–Anderson rules for the constructions of band diagrams of heterojunctions are proposed.
Полупроводниковые гетероструктуры первого рода с непрямой запрещенной зоной на подложках с ориентацией (110)
Authors: Абрамкин Д.С. , Шамирзаев Т.С.
Published: April 2019

AbstractType-I indirect-gap heterostructures are convenient objects for studying the spin dynamics of localized excitons, which are difficult to investigate in heterostructures of other types. It is shown that structures with such an energy spectrum can be formed from III–V binary compounds on substrates with the (110) orientation. The effect of the strain distribution and conduction-band structure in quasimomentum space on the energy spectrum of electronic states in the heterostructures is discussed.
Локализованные экситоны в спектре оптического поглощения оксида цинка, легированного марганцем
Authors: Соколов В.И. , Груздев Н.Б. , Важенин В.А. , Фокин А.В. , Дружинин А.В.
Published: April 2019

AbstractThe results of the study of optical absorption and EPR signals of single crystals of zinc oxide doped with manganese are presented. A broad impurity absorption band with the threshold energy about 2.1 eV, which was treated as a result of charge transfer transitions, has been observed for a long time in ZnO : Mn absorption spectra. In absorption spectra of a polarized light at 4.2 and 77.3 K, we first detected several lines of different intensity in a 1.877–1.936 eV range of energies of the light quanta. The observed lines are attributed to a donor exciton [( d ^5 + h ) e ] that emerges as a result of the Coulomb binding a free s electron and a hole, which is localized on p – d hybridized states. The EPR spectra of Mn^2+ ion signals, when corresponding to the impurity absorption band exposed to light, are found to be not photosensitive. The obtained results indicate that the ZnO : Mn impurity absorption is due to transitions from antibonding p – d hybridized DBH states to the conduction band.
Особенности конкуренции спиновой и псевдоспиновой подсистем в модельном купрате
Authors: Панов Ю.Д. , Улитко В.А. , Будрин К.С. , Ясинская Д.Н. , Чиков А.А.
Published: April 2019

We consider the competition of magnetic and charge ordering in model cuprate within the framework of the simplified static 2D spin-pseudospin model. This model is equivalent to the 2D dilute antiferromagnetic (AFM) Ising model with charged impurities. We present the mean-field results for the system under study and make a brief comparison with classicalMonte Carlo (MC) calculations. Numerical simulations show that the cases of strong exchange and strong charge correlation differ qualitatively. For a strong exchange, the AFM phase is unstable with respect to the phase separation (PS) into the pseudospin (charge) and magnetic (spin) subsystems, which behave like immiscible quantum liquids. An analytical expression was obtained for the PS temperature.
The research was supported by the Government of the Russian Federation, Program 02.A03.21.0006 and by the Ministry of Education and Science of the Russian Federation, projects Nos. 2277 and 5719, and RFBR N 18-32-0083718.
ЯМР-исследование магнитной структуры и сверхтонких взаимодействий в бинарном гелимагнетике FeP
Authors: Гиппиус A.A. , Журенко С.В. , Buttgen N. , Schadler M. , Морозов И.В. , Москвин А.С.
Published: April 2019

AbstractAn NMR analysis of ^31P nuclei in metallic iron phosphide FeP has been performed both in a zero field and by sweeping the external magnetic field at several fixed frequencies with the aim of revealing and investigating the transformation of the magnetic helical structure of FeP. The NMR lineshape gradually changes with an increase in the field strength from trapezoidal (in weak fields) to pronounced asymmetric with two peaks (in strong fields). The former shape is typical of NMR spectra of powder samples under an applied magnetic field, while the latter is characteristic of NMR spectra of nonmagnetic atoms in single-crystalline helimagnetics. The observed transformation of the FeP NMR spectrum evidences in favor of the spin-reorientation transition of a spin-flop type in FeP at strong external fields.
Влияние орбитального упорядочения на спектры магнитного резонанса в зарядово-упорядоченных и фрустрированных манганитах
Authors: Гончарь Л.Э.
Published: April 2019

A theoretical study of the interrelation of the crystal structure, charge, orbital, and magnetic subsystems in R1–xAxMnO3 charge-ordered manganites has been carried out (where R3+ is the rare earth ion,
A2+ is the alkaline earth metal ion, x = 0.5, 2/3). The model of orbital-dependent exchange interactions and
single-ion anisotropy is used. The presence of quasi-low-dimensional magnetic structures is exhibited. The
spin waves spectra and antiferromagnetic resonance spectra are calculated.
О кристаллических полях в REPd-=SUB=-3-=/SUB=-S-=SUB=-4-=/SUB=-
Authors: Еремин М.В. , Нурмухаметов А.Р.
Published: April 2019

AbstractThe possible crystal field parameters in the RPd_3S_4 compounds, where R = Ce, Pr, Nd, Dy, and Er, are discussed on the basis on the available experimental data on neutron scattering and field dependences of magnetic susceptibilities at various temperatures. The values of splittings of the lowest multiplets and wave functions of ground states are calculated.
Люминесценция примесных Pr-=SUP=-3+-=/SUP=--центров и дефектов в Sr-=SUB=-9-=/SUB=-Sc(PO-=SUB=-4-=/SUB=-)-=SUB=-7-=/SUB=-:Pr-=SUP=-3+-=/SUP=-
Authors: Пустоваров В.А. , Ивановских К.В. , Хатченко Ю.Е. , Иванов В.Ю. , Bettinelli M. , Shi Q.
Published: April 2019

AbstractThe spectroscopic characteristics and luminescence decay kinetics of Sr_9Sc(PO_4)_7:Pr^3+(1%) were investigated using synchrotron radiation of ultraviolet (UV), vacuum ultraviolet (VUV) and X-ray ranges, as well as pulsed cathodoluminescence (PCL) methods at temperatures of 10, 90, and 295 K. The luminescence spectra contain three groups of bands and lines. In the UV range, the observed bands correspond to interconfigurational 5 d → 4 f transitions in Pr^3+ ions. In the visible spectrum, the wide luminescence band of defects dominates, as well as narrow lines associated with intraconfigurational 4 f → 4 f transitions in Pr^3+ ions. When excited by an electron beam (5 Hz), the main component with a decay time τ ∼ 17 ns dominates in the decay kinetics of the 5 d → 4 f luminescence. The decay kinetics of 5 d → 4 f luminescence upon excitation with high-frequency (τ ∼ 8 MHz) synchrotron radiation of the X-ray range contains a fast component (τ ∼ 15 ns) against the background of the slow component of the μs-range. An effective nonradiative energy transfer is observed from impurity centers to defects, as well as from the host to Pr^3+ ions and defects.
Природа аномальной красной люминесценции в нелинейно-оптических кристаллах K-=SUB=-2-=/SUB=-Al-=SUB=-2-=/SUB=-B-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=- : Fe
Authors: Огородников И.Н. , Пустоваров В.А.
Published: April 2019

In this work, the spectra of anomalously intense luminescence at 1.675 eV (FWHM= 0.173 eV) in wide-gap (180–3600 nm) nonlinear-optical crystals K2Al2B2O7 were observed experimentally for the first time upon excitation in the spectral region of 4–5 harmonics of the fundamental frequency of the Nd3+ radiation. Using low-temperature (7–293 K) luminescence-optical spectroscopy with selective excitation by synchrotron radiation, it was shown that red luminescence occurs at intracenter 4T1(4G)→ 6A1(6S) transitions in impurity Fe3+ ions with a concentration less than 2 ppm. The high excitation efficiency in the exciton region is due to the partial overlapping of the fundamental absorption edge of the crystal, where mobile excitons are excited, and the broad absorption band with O– Fe charge transfer with a maximum at 6.5 eV. The spectrum and temperature dependence of the luminescence are due to the superposition of two types of luminescence centers (activation energies 9 and 20 meV) based on Fe3+ impurity ions located in regular Al3+ positions of two nonequivalent Al2O7 clusters.
Transferability of crystal-field parameters for rare-earth ions in Y-=SUB=-2-=/SUB=-SiO-=SUB=-5-=/SUB=- tested by Zeeman Spectroscopy -=SUP=-*-=/SUP=-
Authors: Jobbitt N.L. , Patchett S.J. , Alizadeh Y. , Reid M.F. , Wells J.-P.R. , Horvath S.P. , Longdell J.J. , Ferrier A. , Goldner P.
Published: April 2019

AbstractZeeman spectroscopy is used to demonstrate that phenomenological crystal-field parameters determined for the two C _1 point-group symmetry sites in Er^3+:Y_2SiO_5 may be transferred to other ions. The two crystallographic six-and seven-coordinate substitutional sites may be distinguished by comparing the spectra with crystal-field calculations.
Деформационное уширение и тонкая структура спектральных линий в оптических спектрах диэлектрических кристаллов, содержащих редкоземельные ионы
Authors: Абишев Н.М. , Байбеков Э.И. , Малкин Б.З. , Попова М.Н. , Пыталев Д.С. , Климин С.А.
Published: April 2019

AbstractThe procedure of calculation of the spectral line shape in optical spectra of rare-earth ions in crystals with the inclusion of random deformations of an elastically anisotropic crystal lattice caused by point defects is developed. The distribution function of components of the random strain tensor in the case of a low defect concentration is obtained as the generalized six-dimensional Lorentz distribution. The distribution function parameters are represented by the integral functional of the strain tensor components on a sphere of unit radius containing an isotropic point defect in its center. The numerical calculations of the strain tensors induced by point defects and the parameters of the distribution functions of random strains in LiLuF_4 and LaAlO_3 crystals have been performed. The calculated envelope with the doublet structure corresponding to the Γ_2(^3 H _4) → Γ_34(^3 H _5) singlet–doublet transition in the absorption spectrum of Pr^3+ ions in the LiLuF_4 crystal agrees well with the data of the measurements.
Статический и динамический вклады в расщепление основного состояния Eu-=SUP=-2+-=/SUP=- в SrMoO-=SUB=-4-=/SUB=-
Authors: Горлов А.Д.
Published: April 2019

AbstractThe EPR spectrum of an Eu^2+ impurity center in a SrMoO_4 single crystal in the temperature range T = 1.8, 111–300 K has been studied, and the temperature changes in the spin Hamiltonian parameters describing the EPR spectrum of odd europium isotopes have been determined. It is shown that small temperature changes in the diagonal parameters of the spin Hamiltonian (for odd Eu^2+ isotopes) $$b_{2}^{0}$$ ( T ) = b _2( F ) + b _2( L ) and $$P_{2}^{0}$$ ( T ) = P _2( F ) + P _2( L ) are explained by the compensation of spin–phonon contributions b _2( F ) and P _2( F ) by the contributions of the lattice thermal expansion b _2( L ) and P _2( L ). The quantities b _2( L ) and P _2( L ) that are dependent on the static lattice parameters at a given temperature, are estimated in terms of the superposition Newman model. Then, the spin–phonon b _2( F ) and P _2( F ) contributions determined by the lattice ion vibrations are separated. An analysis shows that $$b_{2}^{0}$$ ( F ) and $$P_{2}^{0}$$ ( F ) > 0, b _2( L ) and P _2( L ) < 0, and the temperature behavior of the spin–phonon contribution is well described by G. Pfister’s model of local vibrations.
Спектроскопические свойства KPb-=SUB=-2-=/SUB=-Cl-=SUB=-5-=/SUB=- и RbPb-=SUB=-2-=/SUB=-Br-=SUB=-5-=/SUB=-, легированных Er-=SUP=-3+-=/SUP=- и Yb-=SUP=-3+-=/SUP=-
Authors: Серазетдинов А.Р. , Смирнов А.А. , Пустоваров В.А. , Исаенко Л.И.
Published: April 2019

Er3+ doped lead-halide crystals perform a number of properties which make them perspective for practical use in waveguides and spectrum converters. In current work we have studied luminescence spectra dependencies over the excitation wavelength, luminescence intensity dependences over temperature for up-conversion excitation of most significant lines (530, 550 and 650 nm) under 980 nm excitation. Luminescence decay kinetics under 313 nm and 365 nm excitation in KPb2Cl5:Er3+, RbPb2Br5:Er3+ и KPb2Cl5:Er3++Yb3+ have been measured and theoretical estimates of the lifetimes were made in accordance with Judd-Ofelt technique. Received results can be used in laser systems design and for accuracy evaluation when Judd-Ofelt technique for these crystals is applied.
Тушение люминесценции в керамиках оксида алюминия допированных магнием
Authors: Звонарев С.В. , Смирнов Н.О.
Published: April 2019

AbstractThe effect of magnesium impurity on luminescent properties of alumina ceramics sintered at high temperatures under vacuum is studied by pulsed cathodoluminescence, photoluminescence, and thermoluminescence. At dopant concentrations >1 wt %, high-temperature synthesis results in formation of defects associated with magnesium, which were identified in the pulsed cathodoluminescence (520 nm) and photoluminescence (767 nm) spectra, as well as in the thermoluminescence curves (380 K). It is found that increased magnesium concentration leads to luminescence quenching of the intrinsic centers ( F centers) of alumina in the PCL emission band at 400 nm, impurity defects (Mn^4+ and Cr^3+) in the photoluminescence emission bands at 673 and 689 nm, and all the recorded thermoluminescence peaks at 380, 450, and 615 K.
Люминофор ближнего и коротковолнового ИК-диапазона на основе ниобата литий-лантана со структурой кубического граната
Authors: Бакланова Я.В. , Липина О.А. , Максимова Л.Г. , Бакланова И.В. , Чуфаров А.Ю. , Тютюнник А.П. , Зубков В.Г.
Published: April 2019

AbstractCubic garnets activated by neodymium and holmium, Li_6CaLa_2Nb_2O_12:Nd^3+,Ho^3+, were obtained by solid-state method. The main regularities of changes in the luminescence properties of Li_6C-aLa_2Nb_2O_12:Nd^3+,Ho^3+ solid solutions in the visible, near-IR, and short-wave IR ranges under 808 nm laser diode radiation are determined. The energy transfer mechanism between active centers, involving the participation of Nd^3+ ions as sensitizers for the luminescence of Ho^3+ ions, is proposed. Low phonon energy, high luminescence intensity in the range of 2.0–3.0 μm, and weak up-conversion luminescence in the region of 450–780 nm make it possible to consider the cubic lithium–lanthanum niobates Li_6CaLa_2Nb_2O_12:Nd^3+,Ho^3+ as promising phosphors of the short-wave IR range.
О бародиффузии при медленных течениях газовой смеси
Authors: Жданов В.М.
Published: April 2019

AbstractBarodiffusion in slow flows of a gas mixture is studied with an approximation using hydrodynamic equations of motion for the individual mixture components. It is shown that consideration of the viscous momentum transfer and the contribution of Knudsen layers for the mixture flowing in a channel has a considerable effect on the value of the barodiffusion factor. The relations are obtained for the mean diffusion fluxes of components and for the total flux of the mixture in a circular cylindrical capillary; these relations are valid for moderately small Knudsen numbers used for calculation of the diffusion baroeffect and separation effect when the gas mixture flows in a set of capillaries connecting two volumes. The modification of the relations for the barodiffusion factor (and for the diffusion slip coefficient cross-linked with it) allows interpreting the sign alteration of these effects observed experimentally for some gas mixtures at intermediate Knudsen numbers.
Экспериментальная оценка структурно-временных характеристик разрушения материала на основе магнитно-импульсного нагружения кольцевых образцов
Authors: Морозов В.А. , Петров Ю.В. , Сухов В.Д.
Published: April 2019

AbstractThe study of fracture of thin aluminum rings due to shock loading generated by magnetic-pulse method was performed. This method provides experimental results on dynamic fracture under conditions of pure tension for a wide range of loading conditions. To simulate rapture of the ring samples a structural-temporal fracture criterion was applied. This criterion allows for analysis of the effects which are characteristic for the dynamic experiments. The fracture incubation time value and ultimate stresses are calculated for the aluminum rings subjected to pulse loading. An analytical relationship between the critical stress and the fracture time are obtained and this relation is in good agreement with the experimental data.
Рентгеновская диагностика дефектов микроструктуры кристаллов кремния, облученных ионами водорода
Authors: Асадчиков В.Е. , Дьячкова И.Г. , Золотов Д.А. , Кривоносов Ю.С. , Чуховский Ф.Н.
Published: April 2019

AbstractFeatures of formation and transformation of radiation defects in near-surface layers of silicon plates that are implanted with hydrogen ions are studied. Using the method of high-resolution double-crystal X-ray diffractometry, values of the main parameters, such as mean effective thickness L _eff and mean relative deformation Δ a / a of a doped layer, are determined depending on the implantation dose and substrate temperature.
Новая технология создания высокочувствительных сегнетопьезоэлектрических материалов на основе гибрида микро- и наноструктурированных полимеров
Authors: Курбанов М.А. , Татардар Ф.Н. , Сафаров Н.А. , Рамазанова И.С. , Дадашев З.А. , Фараджзаде И.А. , Азизова К.К. , Гочуева А.Ф.
Published: April 2019

AbstractFabrication of composites based on micro- and nanostructured hybrid polymers have been studied. A new technology for nanoparticle immobilization in the polymer matrix of the composite has been suggested. Its essence is to produce functional electronegative polymer segments in the polymer matrix, which are the main agents preventing nanoparticle mobilization in the polymer phase of a composite.
Оптический аналог зонной плавки при комнатной температуре
Authors: Стрекалов В.Н.
Published: April 2019

AbstractThe conditions at which the birth of photoelectrons in a semiconductor or transparent dielectric leads to the appearance of a force causing drift of impurities are found. Drift occurs in the same direction as the displacement of the focal region of the radiation, which excites minority charge carriers. The use of this condition made it possible to show that drift can be more noticeable than diffusion. This process, which can be considered an optical analog of zone melting, is especially important for thin films.
Брэгговские дефлекторы волновых потоков для мощных релятивистских мазеров
Authors: Аржанников A.В. , Гинзбург Н.С. , Заславский В.Ю. , Калинин П.В. , Песков Н.Ю. , Сергеев А.С. , Синицкий С.Л.
Published: April 2019

AbstractQuasi-optical Bragg structures that represent sections of planar waveguides with tilted (with respect to the beam propagation direction) corrugation are studied. It is shown that such structures may serve as efficient deflectors for high-power wave fluxes and, hence, can be used for separation of microwave radiation and electron beam in relativistic masers. The corrugation configuration is optimized to increase the efficiency of transformation of wave fluxes to the transverse direction and improve uniformity of the spatial distribution of scattered radiation. The simulated results are verified using cold electrodynamic tests.
Оптические и фотоэлектрические свойства тонких пленок GaS и гетероструктуры GaS/InSe
Authors: Гусейнов А.Г. , Салманов В.М. , Мамедов Р.М. , Салманова А.А. , Ахмедова Ф.М.
Published: April 2019

AbstractGaS thin films have been grown by the SILAR method, their structures have been analyzed, and their optical and photoelectric properties have been investigated. The internal structure of the samples obtained have been studied using X-ray diffraction (XRD) analysis, atomic force microscopy (AFM), energy-dispersive X-ray (EDX) spectroscopy, and scanning electron microscopy (SEM). The GaS band gap has been determined from the absorption spectrum. p -GaS/ n -InSe heterojunctions have been formed on the basis of GaS crystals and InSe thin films. Current–voltage, optical, photoelectric, and luminescence characteristics of p -GaS/ n -InSe heterojunctions have been experimentally investigated.