检索结果-南通市图书馆

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

在线全文

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

静电纺丝法制备铁酸锌纳米纤维及其气敏性能研究（英文）

在线全文

学校读者我要写书评

暂无评论

稀有金属材料与工程 2019年第5期48卷 1371-1379页

作者：储向峰干正强白林山董永平 marina n. rumyantseva 安徽工业大学安徽马鞍山243002 Moscow State University Moscow 119991Russia

与零维、二维和三维纳米材料相比,一维纳米材料具有优异的气敏性能。以Zn(nO3)2·6H2O和Fe(nO3)3·9H2O为原料通过静电纺丝的方法制备了一维铁酸锌纳米纤维。利用TG-DSC分析了材料的前驱体,用XRD、SEM、TEM、FT-IR、BET和XPS对材料进行... 详细信息

与零维、二维和三维纳米材料相比,一维纳米材料具有优异的气敏性能。以Zn(nO3)2·6H2O和Fe(nO3)3·9H2O为原料通过静电纺丝的方法制备了一维铁酸锌纳米纤维。利用TG-DSC分析了材料的前驱体,用XRD、SEM、TEM、FT-IR、BET和XPS对材料进行了表征,并且对材料的气敏性能进行了研究。结果表明,在煅烧温度为500℃下获得的材料呈现出纳米纤维的形貌;基于500℃下获得的铁酸锌纳米纤维的元件,在工作温度为190℃下对丙酮表现出较高灵敏度和高选择性,S1000μL/L丙酮/S1000μL/L乙醇=8;当丙酮浓度低至1μL/L时,灵敏度仍能达到1.1。

关键词：纳米纤维丙酮传感器选择性静电纺丝铁酸锌

Observation of the hyperfine structure and anticrossings of hyperfine levels in the luminescence spectra of LiYF4:Ho3+

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2022年第9期11卷 2155-2165页

作者： KIRILL n.BOLDYREV BORIS Z.MALKIn marina n.POPOVA Institute of Spectroscopy Russian Academy of SciencesTroitskMoscow 108840Russia Kazan Federal University Kazan 420008Russia

Resolved hyperfine structure and narrow inhomogeneously broadened lines in the optical spectra of a rare-earth-doped crystal are favorable for the implementation of various ***,a well-resolved hyperfine structure in the photoluminescence spectra of LiYF4:Ho single crystals and the anticrossings of hyperfine levels in a magnetic field are demonstrated using a self-made setup based on a Bruker 125HR high-resolution Fourier *** is the first observation of the resolved hyperfine structure and anticrossing hyperfine levels in the luminescence spectra of a *** narrowest spectral linewidth is only 0.0022 *** fact together with a large value of the magnetic g factor of several crystal-field states creates prerequisites for developing magnetic field sensors,which can be in demand in modern quantum information technology devices operating at low *** small random lattice strains characterizing the quality of a crystal can be detected using anticrossing points.

关键词： spectra luminescence hyperfine

Crystal-field levels of nd3+ in a new langasite compound nd3CrGe3Be2O14

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2019年第11期37卷 1250-1254页

作者： Sergei A.Klimin Boris V.Mill marina n.Popova Institute of Spectroscopy Russian Academy of SciencesTroitskMoscow 108840Russia Faculty of Physics M.V.Lomonosov Moscow State UniversityMoscow 119991Russia

We report on the crystal-field(CF)levels of nd^3+in nd3CrGe3Be2O14,a representative of recently synthesized Be-containing *** are the first in the family to contain two magnetic subsystems,1 D chromium and Kagome-like rare-earth ***-resolution broad-band temperature-dependent spectra allow us to find all five CF Kramers doublets of the ground 4I9/2 CF multiplet and 38 levels of the excited 4I11/2,13/2,15/2,4F3/2,4F5/2+2H9/2,4F7/2+4S3/2 and 4F9/2 CF *** data form a basis for a future exploration of this interesting two-sublattice magnet with frustrated *** transitions between Kramers doublets of nd^3+indicate magnetic activity of 1D-chromium chains at T<20 K.

关键词： Langasite Two magnetic subsystems High-resolution spectroscopy Crystal-field levels Magnetic correlations Rare earths

Advances and challenges in diagnosing and managing adult autoimmune enteropathy

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2025年第2期31卷 128-131页

作者： Grigorios Christodoulidis Sara E Agko marina n Kouliou Konstantinos E Koumarelas Dimitris Zacharoulis Department of General Surgery University Hospital of LarissaLarissa 41110Greece Department of Intensive Care Unit Asklepios Paulinen Clinic WiesbadenWiesbaden 65197Germany Department of Emergency Medicine General Hospital of LarissaLarissa 41221Greece Department of Surgery University Hospital of LarissaLarissa 41334Greece

Autoimmune enteropathy(AIE)is a rare immune mediated disorder primarily affecting children,characterized by chronic diarrhea,malabsorption,vomiting,weight loss and villous *** has also been observed in adults presenting diagnostic and treatment challenges due to its overlap with other gastrointestinal disorders such as celiac *** diagnostic criteria for AIE include small bowel villous atrophy,lack of response to dietary restrictions,presence of anti-enterocyte antibodies,and predisposition to autoimmunity without severe *** criteria emphasize characteristic histological findings and exclusion of other causes of villous *** is associated with various autoimmune disorders and can present with overlapping features with Celiac disease,including villous atrophy but without significant intraepithelial *** primarily involves immunosuppression using corticosteroids,calcineurin inhibitors,and anti-tumor necrosis factor therapy,alongside nutri-tional *** the challenges,understanding AIE’s diverse manifest-ations and improving diagnostic criteria are essential for effective management and improved patient *** research is needed to elucidate the pathogenesis,disease progression and long-term outcomes of AIE.

关键词： Autoimmune enteropathy Diagnosis Prognosis Adult autoimmune enter-opathy and challenges Autoimmune enteropathy and treatment Autoimmune enteropathy and diagnostic criteria Pathophysiology of autoimmune enteropathy

Model acupuncture point:Bone marrow-derived stromal stem cells are moved by a weak electromagnetic field

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Stem Cells 2016年第10期8卷 342-354页

作者： Artem n Emelyanov marina V Borisova Vera V Kiryanova Laboratory of High Laser and Magnetic Technology North-Western State Medical University Training Laboratory of Physical Chemistry Institute of ChemistrySt. Petersburg State University Department of Physical Therapy and Rehabilitation North-Western State Medical University

AIM To show the existence of a structural formative role of magnetic fields(MFs) with respect to biological objects by using our proposed model of an *** We introduced a magnetised 10-100 μT metal rod(needle) into culture dishes with a negatively charged working surface and observed during 24 h how cells were arranged by MFs and by electrical fields(EFs) when attached. Rat and human bone marrow-derived stromal stem cells(r BMSCs and h BMSCs), human nonadherent mononuclear blood cells, nCTCs and A172 cells, and Escherichia coli(E. coli) were evaluated. The dish containing BMSCs was defined as the model of an acupoint. r BMSCs proliferative activity affected by the needle was investigated. For investigating electromagnetic field structures, we used the gas discharge visualisation(GDV) *** During 24 h of incubation in 50-mm culture dishes, BMSCs or the nonadherent cells accumulated into a central heap in each dish. BMSCs formed a torus(central ring) with an inner diameter of approximately10 mm only upon the introduction of the needle in the centre of the dish. The cells did not show these effects in 35- or 90-mm culture dishes or hydrophobic dishes or rectangular cuvettes. nCTCs and A172 cells showed unstable the effects and only up to two weeks after thawing. Moreover, we observed that the appearance of these effects depended on the season. In winter, BMSCs showed no the effects. GDV experiments revealed that the resonant annular illumination gradually formed from 10 to 18-20 s in polar solutions with and without cell suspension of BMSCs, nCTCs and E. coli when using circular 50-mm dishes, stimulation at 115 V and switching of the electrode poles at 1 kH z. All these data demonstrate the resonant nature of the central ring. Significant influence of MFs on the rB MSC proliferation rate was not *** BMSCs can be moved by MFs when in the presence of a constant EF and MF, when the cells are in the responsive functional state, and whe

关键词： Stem cell movement Magnetic targeting Acupuncture Model acupoint Frizzled-related protein Biology resonance Cytoplasm movement Glycocalyx

Geographical Distribution and Morphological Variability of the Rapid Racerunner,Eremias velox (Pallas,1771)(Reptilia,Lacertidae) in the Eastern Periphery of Its Range

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Herpetological Research 2019年第4期10卷 230-245页

作者： marina A.CHIRIKOVA Tatjana n.DUJSEBAYEVA Jinlong LIU Xianguang GUO Institute of Zoology Ministry of Education and SciencesAlmaty 050060Kazakhstan Chengdu Institute of Biology Chinese Academy of SciencesChengdu 610041China

Phenotypic traits are usually correlated with the environment where organism occurs. In this study, the distribution of Eremias velox in the eastern periphery of its range was specified, and its morphological variation was analyzed. Linear dimensions, pholidosis, coloration and pattern features were compared among 135 specimens from nine populations inhabiting the Balkhash, Ili and Alakol basins, Junggar and Turpan depressions in the territory of Southeast Kazakhstan and Xinjiang, northwest China. The populations from the Junggar Depression(Kuytun, Shihezi and Urumqi) were characterized by higher mean values of linear characters, the number of scales across the middle of the body and gular, and were similar in the dominant coloration patterns. Small size, dark coloration and almost complete dominance of the striped-type coloration pattern among the specimens from the Alakol Lake islands seem to have an adaptive significance associated with the isolation of the population and type of their habitats. The subspecies Eremias velox roborowskii(endemic to the Turpan Depression) is elevated to species level, as supported by morphological divergence congruent with molecular and geographical data, including its peculiar type of coloration pattern, significantly lower amount of femoral pores and a higher percentage of specimens with one enlarged preanal scale(72.7%). These results together confirm a high degree of variability in morphology for ***х in the eastern periphery of its range, reflecting a complex orography and the existence of multiple geographical barriers in this territory.

关键词： Eremias velox Kazakhstan Xinjiang habitat pholidosis coloration intraspecies differentiation

Universal Enveloping Algebras of Simple Symplectic Anti-Jordan Triple Systems

在线全文

学校读者我要写书评

暂无评论

Algebra Colloquium 2015年第2期22卷 281-292页

作者： marina Tvalavadze University of Toronto (Mississauga Campus) Mathematical and Computational Sciences3359 Mississauga Rd. n Mississauga ON L5L 1C6 Canada

In this work we axe concerned with the universal associative envelope of a finite-dimensional simple symplectic anti-Jordan triple system （AJTS）. We prove that if T is a triple system as above, then there exists an associative algebra U（T） and an injective homomorphism ε ： T→ U（T）, where U（T） is an AJTS under the triple product defined by （a, b, c） = abc- cba. Moreover, U（T） is a universal object with respect to such homomorphisms. We explicitly determine the PBW-basis of U（T）, the center Z（U（T）） and the Gelfand-Kirillov dimension of U（T）.

关键词： anti-Jordan triple systems universal enveloping algebras central elements,PBW-bases