检索结果-南通市图书馆

Challenges in differential diagnosis between obstructive and non-obstructive azoospermia

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

UroPrecision 2024年第1期2卷 30-35页

作者： Safar Gamidov Taras Shatylko Alikhan Tambiev Natig Gasanov Alina popova Abdalrahman Alrawashdeh Gennadiy Sukhikh V.I.Kulakov National Medical Research Center of Obstetrics Gynecology and PerinatologyMoscowRussia Sechenov University MoscowRussia

Background:Some cases of non-obstructive azoospermia(NOA)are characterized by normal clinical parameters,including testicular volume and levels of reproductive hormones,mimicking obstructive azoospermia(OA).Methods:We performed a retrospective review of a consecutive series of 1417 patients undergoing primary surgical sperm retrieval between 2014 and ***-stimulating hormone(FSH)level below 7.6 IU/l and normal testicular size with a long axis measurement>4.6 cm were used as criteria to suspect ***:Four hundred and eighteen patients with normal testicular volume and FSH levels had an initial diagnosis of *** them,243(58.1%)had histological signs of spermatogenic dysfunction,and 175(41.9%)had true *** hundred eleven patients had long-standing obstruction(median:16.5 years)with a median Bergmann-Kliesch score(BKS)of 5(interquartile range[IQR]:4-6)and 100%sperm retrieval rate(SRR),though some required microdissection testicular sperm extraction(microTESE).Fifty-eight patients with a history of epididymo-orchitis had a median BKS of 4(IQR:2-6)and 100%*** patients with a history of unjustified medical treatment for male infertility had a median BKS of 3(IQR:1-4)and 80%***-four patients had uniform maturation arrest with a 5.5%SRR on ***:Men with normal testicular volume and FSH level may have evidence of spermatogenic failure on *** with complicated seminal tract obstruction commonly have hypospermatogenesis,but true NOA caused by uniform maturation arrest may also be *** counseling for suspected OA should not be overly optimistic,and couples should be warned about possibility of conversion to microTESE and risks of negative sperm retrieval.

关键词： azoospermia male infertility sperm retrieval

十九至二十世纪之交俄罗斯的中亚考察与奥登堡的敦煌探险

在线全文

学校读者我要写书评

暂无评论

敦煌研究 2024年第4期 140-150页

作者：伊琳娜·波波娃王平先俄罗斯科学院东方文献研究所敦煌研究院编辑部

19—20世纪之交，中亚是英俄两国角逐的舞台。为了获得新市场和原材料来源地的控制权，沙俄开始对中亚进行了一系列的探险考察。在此背景下，谢尔盖·奥登堡（S.F. Oldenburg,1863—1934）先后主导了前往中国新疆和敦煌的两次探险。1914... 详细信息

19—20世纪之交，中亚是英俄两国角逐的舞台。为了获得新市场和原材料来源地的控制权，沙俄开始对中亚进行了一系列的探险考察。在此背景下，谢尔盖·奥登堡（S.F. Oldenburg,1863—1934）先后主导了前往中国新疆和敦煌的两次探险。1914—1915年，奥登堡率领探险队前往敦煌对莫高窟进行了详细的考古调查，并通过各种方式收集了大量古代文献与文物。奥登堡敦煌探险收集品后来分藏于埃尔米塔什博物馆、俄罗斯科学院档案馆圣彼得堡分馆和俄罗斯科学院东方文献研究所，自那以来关于该收集品已有大量研究成果问世。

关键词：俄罗斯中亚考察奥登堡敦煌探险敦煌写本

High-resolution Fourier spectroscopy as a tool for studying quality of rare-earth-doped crystals

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2014年第3期32卷 230-235页

作者： Marina N.popova Institute of Spectroscopy Russian Academy of Sciences 5 Fizicheskaya Str. 142190 Troitsk Moscow Russia

Three examples were considered of the use of high resolution Fourier-transform optical spectroscopy for studying quality of rare-earth-doped crystals. The first example was connected with defects present in crystals grown by flux techniques. The second example dealt with detection of stresses and deformations in rare-earth-containing crystals, by registering splitting of spectral lines. The third example showed that a very small amount （at the level ofppm） of different RE ions present in a crystal could be determined using high-resolution spectroscopy. This work was carried out by the author＇s group in collaboration with several institutions in Rus- sia and abroad.

关键词： Fourier-transform optical spectroscopy high resolution absorption spectra rare earths

Spectroscopy of compounds from the family of rare-earth orthoborates

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2009年第4期27卷 607-611页

作者： Marina N.popova Institute of Spectroscopy Russian Academy of Sciences 5 Fizicheskaya Str. Troitsk Moscow Region 142190 Russia

This paper is devoted to the rare-earth borates described by the general formula RM3（BO3）4, M = Al, Fe, and Cr, that have non-centrosymmetric trigonal slructure of the natural mineral huntite. It give a brief review of a spectroscopic research on YbAI3（BO3）4 （YbAB）, on a large group of magnetic iron borates, and on NdCra（BO3）4.

关键词： YbAl3(BO3)4 rare-earth iron and chromium borates magnetic ordering Fourier-transform optical spectroscopy

On the metallicity gradient in the Galactic disk

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2020年第4期20卷 123-128页

作者： Alexander Loktin Maria popova Astronomical Observatory Ural Federal UniversityEkaterinburgRussia

The problem of the chemical composition gradient in the Galactic disk is studied based on a sample of metallicity estimates of open star clusters,using Gaia DR2-improved distance estimates.A clearly non-monotonic variation was observed in the average metallicity of clusters with increasing Galactocentric *** can clearly see the metallicity jump of 0.22 in[Fe/H]at a Galactocentric distance of about9.5 kpc,which appears to be linked to the outer boundary of the thinnest and youngest component of the Galactic *** absence of a significant metallicity gradient in the internal(R10 kpc)regions of the disk demonstrates the absence of noticeable metal enrichment at times of the order of the ages corresponding to those of the disk regions under *** data show that the disk experiences noticeable metal enrichment only during the starburst *** significant dependence was identified between the average metallicity and the age of the clusters.

关键词： Galaxy:general Galaxy:disk (Galaxy:)open clusters and associations:general

Timoshenko inclusions in elastic bodies crossing an external boundary at zero angle

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2017年第3期30卷 327-333页

作者： A.M. Khludnev T.S. popova Lavrentyev Institute of Hydrodynamics of R_AS Novosibirsk State University Novosibirsk 630090 Russia North-Eastern Federal University Yakutsk 677000 Russia

The paper concerns an analysis of equilibrium problems for 2D elastic bodies with a thin Timoshenko inclusion crossing an external boundary at zero angle. The inclusion is assumed to be delaminated, thus forming a crack between the inclusion and the body. We consider elastic inclusions as well as rigid inclusions. To prevent a mutual penetration between the crack faces, inequality type boundary conditions are imposed at the crack faces. Theorems of existence and uniqueness are established. Passages to limits are investigated as a rigidity parameter of the elastic inclusion going to infinity.

关键词： Thin Timoshenko inclusion Crack Delamination Fictitious domain method Non-penetration

The research works of Coulomb and Amontons and generalized laws of friction

在线全文

学校读者我要写书评

暂无评论

Friction 2015年第2期3卷 183-190页

作者： Elena popova Valentin L.POPOV Institute of Mechanics Technische Universität Berlin10623Berlin National Research Tomsk State University 634050 TomskRussia

The paper is devoted to the contributions of Coulomb and Amontons to the physics of friction from the viewpoint of current discussions and attempts to formulate generalized laws of friction.

关键词： static friction sliding friction kinetics of friction material dependency history of science

Fine structure and phase composition of Fe–14Mn–1.2C steel:influence of a modified mixture based on refractory metals

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2017年第5期24卷 523-529页

作者： Anna Zykova Natalya popova Mark Kalashnikov Irina Kurzina Tomsk Polytechnic University Tomsk State University of Architecture and Building Chemical Department Tomsk State University

The effect of TiO;,ZrO;and Na;AlF;ultrafine powders on the fine structure and the phase composition of Fe–14Mn–1.2C steel was *** introduction of the ultrafine powders into the melt influenced the grain size,the quantity,and the character of distribution of nonmetallic inclusions in the railroad *** microstructure of castings was improved significantly because of the refinement of the grain structure and an increase of the grain-boundary *** the modifying mixture was introduced into the melt,either the microtwins of one or two intersecting systems or the precipitations of ε-martensite of different types,or simultaneously the microtwins and wafers of ε-martensite,were present in each grain.

关键词： manganese steel fine structure phase composition refractory metals

A Review on the Taxonomic,Evolutionary and Phytogeographic Studies of the Lotus Plant(Nelumbonaceae:Nelumbo)

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2014年第4期88卷 1252-1261页

作者： LI Ya popova SVETLANA YAO Jianxin LI Chengsen Institute of Geology Chinese Academy of Geological Sciences Key Laboratory of Stratigraphy and Paleontology Ministry of Land and Resources of the People's Republic of China State Key Laboratory of Systematic and Evolutionary Botany Institute of BotanyChinese Academy of Sciences Laboratory of Palaeobotany Komarov Botanical InstituteRussian Academy of Sciences

Nelumbo Adans. （Nelumbonaceae） is an important member of the early-diverging eudicots. It contains two extant species： N. nucifera Gaertn. （the Sacred lotus）, distributed in Asia and Australia and N. lutea Willd. （the American lotus）, occurring in North America. This paper reviews the taxonomic, evolutionary and phytogeographic studies of the genus Nelumbo, and also raises scientific questions about it in further paleobotanic research. There are about 30 fossil species of Nelumbo established since the Early Cretaceous. Based on fossil studies, the ancestors of the extant N. nucifera and N. lutea are respectively considered to be N. protospeciosa from the Eocene to Miocene of Eurasia, and N. protolutea from the Eocene of North American. However, molecular systematic studies indicate that N. nucifera and N. lutea are probably split from a common ancestor during the Late Miocene to Early Pliocene, or even the Pleistocene, rather than separate relicts from extinct species on different continents. The characters of lotus stomatal development, seedling morphology as well as its flowering, pollination and fertilization in air reveal that it evolves from the land plants. Fossil data of Nelumbo indicates that the genus first occurs in mid-latitude area of Laurasia in the Early Cretaceous, then becomes widespread in North America and Eurasia and expands into Africa and South America during the Late Cretaceous; the genus probably colonizes the Indian Subcontinent from Asia during the Early Eocene after the collision of India and the Asian plates; the genus becomes extinct in Europe, but survives in Asia and North America during the Quaternary Ice Age, and later forms the present East Asia and North Australia-North America disjunctive distribution.

关键词： taxonomy evolution phytogeography Nelumbo Nelumbonaceae