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Terahertz high-sensitivity SIS mixer based on Nb–AlN–NbN hybrid superconducting tunnel junctions

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Chinese Physics B 2024年第5期33卷 681-686页

作者：刘博梁刘冬姚明金骏达王争李婧史生才 Artem Chekushkin Michael Fominsky Lyudmila Filippenko valery Koshelets Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China Kotel'nikov Institute of Radio Engineering and Electronics Russian Academy of SciencesMoscow 125009Russia

The terahertz band,a unique segment of the electromagnetic spectrum,is crucial for observing the cold,dark universe and plays a pivotal role in cutting-edge scientific research,including the study of cosmic environments that support life and imaging black ***-sensitivity superconductor–insulator–superconductor(SIS)mixers are essential detectors for terahertz astronomical telescopes and interferometric *** to the commonly used classical Nb/AlO_(x)/Nb superconducting tunnel junction,the Nb/AlN/NbN hybrid superconducting tunnel junction has a higher energy gap voltage and can achieve a higher critical current *** makes it particularly promising for the development of ultra-wideband,high-sensitivity coherent detectors or mixers in various scientific research *** this paper,we present a superconducting SIS mixer based on Nb/AlN/NbN parallel-connected twin junctions(PCTJ),which has a bandwidth extending up to490 GHz–720 *** best achieved double-sideband(DSB)noise temperature(sensitivity)is below three times the quantum noise level.

关键词： SIS mixer terahertz gap voltage critical current density hybrid superconducting tunnel junction

Spherically Symmetric Problem of General Relativity for a Fluid Sphere

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Journal of Modern Physics 2024年第4期15卷 401-415页

作者： valery V. Vasiliev Leonid V. Fedorov Institute of Applied Mechanics of Russian Academy of Sciences Moscow Russia

The paper is devoted to a spherically symmetric problem of General Relativity (GR) for a fluid sphere. The problem is solved within the framework of a special geometry of the Riemannian space induced by gravitation. According to this geometry, the four-dimensional Riemannian space is assumed to be Euclidean with respect to the space coordinates and Riemannian with respect to the time coordinate. Such interpretation of the Riemannian space allows us to obtain complete set of GR equations for the external empty space and the internal spaces for incompressible and compressible perfect fluids. The obtained analytical solution for an incompressible fluid is compared with the Schwarzchild solution. For a sphere consisting of compressible fluid or gas, a numerical solution is presented and discussed.

关键词： General Relativity Spherically Symmetric Problem Fluid Sphere

Cluster Analysis of the Roma-BZCAT Blazars

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Research in Astronomy and Astrophysics 2024年第5期24卷 117-139页

作者： Dmitry O.Kudryavtsev Yulia V.Sotnikova Vladislav A.Stolyarov Timur V.Mufakharov valery V.Vlasyuk Margarita L.Khabibullina Alexander G.Mikhailov Yulia V.Cherepkova Special Astrophysical Observatory of the Russian Academy of Sciences Nizhny Arkhyz 369167Russia Astrophysics Group Cavendish LaboratoryUniversity of CambridgeCambridge CB3 OHEUK Kazan Federal University 18 Kremlyovskaya StKazan 420008Russia

Based on the collected multiwavelength data, namely in the radio(NVSS, FIRST, RATAN-600), IR(WISE),optical(Pan-STARRS), UV(GALEX), and X-ray(ROSAT, Swift-XRT) ranges, we have performed a cluster analysis for the blazars of the Roma-BZCAT catalog. Using two machine learning methods, namely a combination of PCA with k-means clustering and Kohonen's self-organizing maps(SOMs), we have constructed an independent classification of the blazars(five classes) and compared the classes with the known Roma-BZCAT classification(FSRQs, BL Lacs, galaxy-dominated BL Lacs, and blazars of an uncertain type) as well as with the high synchrotron peaked(HSP) blazars from the 3HSP catalog and blazars from the TeVCat catalog. The obtained groups demonstrate concordance with the BL Lac/FSRQ classification along with a continuous character of the change in the properties. The group of HSP blazars stands out against the overall distribution. We examine the characteristics of the five groups and demonstrate distinctions in their spectral energy distribution shapes. The effectiveness of the clustering technique for objective analysis of multiparametric arrays of experimental data is demonstrated.

关键词： methods data analysis-galaxies active-(galaxies:)BL Lacertae objects general

Pareto Optimization as the Basic for Selecting Robotic Mechanic Assembly Technologies

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Applied Mathematics 2024年第6期15卷 421-439页

作者： Valerii Kyrylovych Dragoljub Tanovic Dmytro Melnychuk Liudmyla Mohelnytska Petro Melnychuk valery Yanovsky Faculty of Computer-Integrated Technologies Mechatronics and Robotics Zhytomyr Polytechnic State University Zhytomyr Ukraine Faculty of Mechanical Engineering University of Belgrade Belgrade Serbia

The task of selecting robotic mechanic assembly technologies (RMAT) is considered as a multi-criteria optimization task, which in this formulation is solved on the set of previously obtained solutions regarding the selection of RMAT. The purpose of the paper is to increase the efficiency of technological preparation of robotic mechanical assembly production of machine and instrument engineering due to a new approach to the selection of RMAT using Pareto optimization and the peculiarities of the selection task formulation. The novelty consists in the further development of a science-based approach to solving multi-criteria selection task, based on the first proposed formalisms of the specified process, which reflect the peculiarities of the selection task formulation, its meaningful essence and the content of the Pareto optimization method. The practical value of the research lies in the proposed engineering-acceptable approach to solving applied multi-criteria selection tasks on the example of RMAT selection, which is invariant to the statement of the selection task, the dimension of the task, and its meaningful essence. The methods of discrete optimization, fuzzy multi-criteria selection of alternatives, and the Pareto optimization method were used for the research. The main results of this work consist of the development of formalisms and the demonstration of the efficiency of the proposed approach for the applied task of RMAT selection. The peculiarity of the developed approach is the combination of Pareto optimization, performed on a discrete set of local criteria. Directions for further research are presented.

关键词： Multicriteria Optimization Efficiency Fuzzy Multicriteria Selection of Alternatives

Floristic Diversity and Conservation Status of Guineo-Congolese Species in Southeastern Cameroon: The Case of the Gari-Gombo Communal Forest

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Open Journal of Forestry 2024年第1期14卷 87-97页

作者： Boris Nyeck valery Noiha Noumi Nicole Maffo Maffo Victor Awe Djongmo Cedric Djomo Chimi Louis Zapfack Department of Biological Sciences Faculty of Sciences University of Ngaoundéré Ngaoundéré Cameroon Agricultural Research Institute for Development (IRAD) Minko Agricultural Research Station Meyomessala Cameroon Department of live Sciences Higher Teacher Training College University of Bertoua Bertoua Cameroon Department of Plant Biology and Physiology Faculty of Sciences University of Yaoundé I Yaoundé Cameroon Agricultural Research Institute for Development (IRAD) Research Station of Yokadouma Yokadouma Cameroon

The conservation of plant biodiversity has become one of the most important objectives in the sustainable management of Guinean-Congolese ecosystems. However, in the south-east zone of Cameroon, there is a lack of rigor in the management of these forests, which can result in the loss of species of high conservation value. The study was carried out in communal forests in the south-east zone of Cameroon. Its aim was to carry out a floristic inventory and then compare the list of species with the IUCN catalog. Twenty-four plots, each with a surface area of 0.2 ha, were set up in the Gari-Gombo communal forest. All timbers with a DBH ≥ 5 cm were systematically counted. A total of 176 species, belonging to 144 genera and 45 families, were surveyed. Fabaceae (42.08%), Malvaceae (39%), Euphorbiaceae (24.64%), Moraceae (20.92%), Apocynaceae (18.64%), Cecropiaceae (16.60%), Ulmaceae (14.76%), Meliaceae (14.61%), Violaceae (14.08%), Combretaceae (12.67%), Theobroma cacao (21.17%), Baphia leptobotrys (18.06%), Rinorea sp. (14.09%), Musanga cecropioides (12.18%), Terminalia superba (10.32%), Neosloetiopsis kamerunensis (10.14%), Celtis zenkeri (8.29%) and Alstonia boonei (7.77%) were the most important taxa. Nearly 90% of the species in this forest are Guinean species, with a dominance of Guinean-Congolese species (66%). Fourteen (14) threatened species have been identified in the FCGG. This study, which highlights the rich biodiversity of communal forests, is important for guiding biodiversity conservation policies in ecosystems used for production.

关键词： Communal Forest Conservation Status Cameroon Floristic Diversity

Physico-Mechanical Characteristics of Earth Bricks Stabilized with Cement and Padouk Sawdust Residues

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Open Journal of Applied Sciences 2024年第7期14卷 1788-1806页

作者： Gabin Alex Nouemssi Bennis Amine Martin Ndibi Mbozo’O Bonaventure Djeumako Doko K. valery Guy Edgar Ntamack LA2MP: Laboratory of Mechanics Materials and Photonics National School of Agro-Industrial Sciences ENSAI Ngaoundr Cameroun Department of Mechanical and Production Engineering National School of Agro-Industrial Sciences ENSAI Ngaoundr Cameroun LMTM: Laboratory of Mechanics Materials and Thermal National School of Mineral Industry ENIM Rabat Morocco LEMA: Laboratory of Energertic and Applied Mechanics University of Abomey-Calavi Cotonou Benin GMMA: Group of Mechanics Materials and Acoustics Department of Physics Faculty of Sciences-EGCIM Ngaoundr Cameroun

The objective of this work is to improve the physical and mechanical properties of stabilized earth blocks (BTC) used in construction in the Ndé department of Cameroon. To achieve this, two stabilizers, cement and sawdust, were used at varying percentages of 0%, 4%, 6%, and 8%. Physical characterization tests, including natural water content, specific weight, jar test, Protor, and Atterberg limits, were conducted. Additionally, mechanical tests, such as compression and three-point bending, were performed. The results show that as the amount of stabilizer increases, the density of BTC decreases. The samples with 8% sawdust have the highest density, while those without stabilizers have the lowest. Porosity decreases as sawdust and cement content increases, with smaller values observed in samples with 8% sawdust or cement. Our tests indicate that blocks stabilized with cement have slightly higher compressive strength than those stabilized with sawdust. However, the water absorption rate increases with higher sawdust content.

关键词： Earth block Cement Sawdust Physico-mechanical Characteristics Bangante West Cameroon

Physico-Chemical and Nutritional Properties of a Food Broth Based on Nere (Parkia biglobosa)

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Food and Nutrition Sciences 2024年第5期15卷 377-389页

作者： Lassana Bamba Gervais Melaine M’Boh N’Gbésso Amos Ekissi Kipré Laurent Séri Gnogbo Alexis Bahi Koffi Pierre valery Niaba Allico Joseph Djaman Grah Avit Maxwell Beugre Laboratory of Agro-Valorization Department of Agroforesterie Jean Lorougnon Gu&#233d&#233 University Daloa C&#244te d&#8217Ivoire Medical and Fundamental Biochemistry Department Institut Pasteur of C&#244te d&#8217Ivoire Abidjan C&#244te d&#8217Ivoire Laboratory of Biotechnology Agriculture and Valorization of Biological Resources Department of Biosciences Felix Houphouet-Boigny University Abidjan Cote d&#8217Ivoire Biology and Health Laboratory Department of Biosciences Felix Houphouet-Boigny University Abidjan C&#244te d&#8217Ivoire

Purpose: Diet and eating habits are major risk factors for the health and the development of disease, such as, for example, metabolic disorder leading to cardiovascular pathology and cancer, decreased immunity exposing to infections. This study of the physico-chemical and nutritional properties of a soumara-based food broth was carried out with the aim of promoting the consumption of organic broth made from nere seeds (soumara). That is to alleviate certain metabolic diseases, which is a matter of food safety, and also to limit the risk for the health about the consumption of some cooking stocks on the market. Methods: Several natural ingredients such as nere seeds (soumara), ginger, black pepper, parsley and garlic were used to create a nere-based stock. All these ingredients were freeze-dried and the powder obtained was used to make the broth, regarding their physical and chemical properties. Results: The broth had a good protein content of 17.41 ± 0.367 g/100g, a lipid content of 16.80 ± 0.08 g/100g and a fiber content of 8.66 ± 0.04 g/100g. In terms of nutritional values, the broth showed good levels of calcium 184.21 ± 0.09 mg/100g, potassium 50.04 ± 1.45 mg/100g and iron and zinc. In terms of antioxidant activity, the broth also showed good antioxidant activity. Conclusion: Regarding the properties of our food broth, whose composition is based on natural ingredients, could be recommended for consumption and, its properties, could play an important role in preventing and combating certain metabolic diseases.

关键词： Food Broth Nere Physico-Chemical Properties Nutrition Food Safety

19世纪末20世纪初俄国政府关于北高加索石油工业的发展政策

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学习与探索 2024年第3期 168-175页

作者： [俄]瓦列里·斯捷潘诺夫赵博雅(译) 俄罗斯科学院经济研究所圣彼得堡国立大学吉林大学东北亚研究院

19世纪末20世纪初,俄国政府在予以巴库石油工业绝对优先权的同时,也在其他地区勘探和开发油田。早在1894年,俄国政府就对北高加索油田租期及勘探进行了规定,随后,陆续出台了关于北高加索石油运输、石油业务经费使用、允许外国资本参与... 详细信息

19世纪末20世纪初,俄国政府在予以巴库石油工业绝对优先权的同时,也在其他地区勘探和开发油田。早在1894年,俄国政府就对北高加索油田租期及勘探进行了规定,随后,陆续出台了关于北高加索石油运输、石油业务经费使用、允许外国资本参与北高加索石油工业等规定。俄国政府的政策促进了北高加索地区石油工业的发展和现代化,但其期待出现与巴库地区规模相当的新采油中心的愿望却没能实现。

关键词：俄国北高加索石油工业库班捷列克

Use of folic acid nanosensors with excellent photostability for hybrid imaging

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2022年第9期23卷 784-790页

作者： Denis KUZNETSOV Sergey DEZHUROV Dmitri KRYLSKY valery NOVIKOV valery NESCHISLIAEV Anastasia KUZNETSOVA G.N.Gabrichevsky Scientific and Research Institute of Epidemiology and Microbiology Moscow125212Russia Research Institute of Applied Acoustics Center of High TechnologiesDubna141980Russia Perm State Medical University Perm614000Russia Perm State Pharmaceutical Academy Perm614990Russia Perm State Humanitarian Pedagogical University Perm614990Russia

Sentinel lymph node(SLN)mapping and tumorboundary delineation play a key role in cancer surgery,as they have great potential to reduce surgical intervention and increase relapse-free survival rates of *** autofluorescence imaging(AFI)method can improve the efficiency of tumor delineation and optimize the scope of surgical intervention,but there are still no fluorescent drugs that can be used with such a method to form a hybrid imaging *** problem is bleaching when fluorescent dyes are conjugated with folic *** study reports,for the first time,nanosensors with excellent photostability and compatibility with endoscopes for AFI,which makes simultaneous hybrid imaging *** functionalization of the quantum dot(QD)surfaces,we found that they bound effectively to MCF-7 cancer *** diagnostic value of simultaneous hybrid imaging using common AFI equipment in delineating tumor boundaries and mapping SLN can reduce the cost of diagnosis and increase its reliability.

关键词： diagnosis drugs mapping