检索结果-南通市图书馆

激光辐射波长和脉冲寿命对碲化镉熔化阈值的影响

在线全文

学校读者我要写书评

暂无评论

材料导报 2024年第7期38卷 40-45页

作者：列维茨基·谢尔盖曹泽祥柯巴·亚历山大柯巴·玛丽亚乌克兰国家科学院半导体物理研究所基辅03028 乌克兰国立技术大学物理技术学院基辅03058 乌克兰国民警卫研究所国家安全系基辅03028

碲化镉的相对分子量为240,密度为5.885 g/cm^(3),熔点为1092℃。碲化镉是一种Ⅱ-Ⅵ族的化合物半导体材料,属于直接带隙型,带隙宽度为1.56 ev。碲化镉是制造X射线、伽马射线和红外线探测器的基本材料。对碲化镉的特别关注主要是由于其大... 详细信息

碲化镉的相对分子量为240,密度为5.885 g/cm^(3),熔点为1092℃。碲化镉是一种Ⅱ-Ⅵ族的化合物半导体材料,属于直接带隙型,带隙宽度为1.56 ev。碲化镉是制造X射线、伽马射线和红外线探测器的基本材料。对碲化镉的特别关注主要是由于其大原子数和大的光电吸收截面。在基于CdTe的伽马辐射势垒探测器结构中,其表面的处理方法之一是纳秒激光照射,在某些情况下,纳秒激光照射可以在触点(Ag、In、Au)和势垒形成的技术处理阶段优化所需的表面参数。另一种方法是在脉冲激光照射下在碲化镉表面形成有序的纳米结构。对基于半导体及其结构的脉冲激光器,可根据其不同的脉冲持续时间τ_(p)和辐射波长λ将其分类。例如,红宝石激光器(λ=694 nm)、钕激光器(一次谐波1064 nm和两次谐波532 nm)、准分子KrF激光器(248 nm)和XeF激光器(351 nm)等,其脉冲持续时间分别为7、20、80、120 ns。这些激光器常被应用于表面修饰等领域。因此,往往有必要事先知道或至少估计在脉冲激光辐射下碲化镉表面的熔化温度和阈值,这取决于激光脉冲持续时间τ_(p)、辐射波长(光吸收系数α(λ))以及碲化镉表面本身的电物理参数,特别是表面重组率S和非平衡电荷载流子的寿命。这些参数取决于表面处理的方法和掺杂物的浓度。在上述情况下,实验研究是非常耗费人力和时间的,因此基于τ_(p)、α(λ)和碲化镉表面本身的电物理参数对融化阈值th和表面温度进行理论计算变得非常重要。本工作采用激光照射碲化镉,辐射波长为300~800 nm,脉冲持续时间为7~120 ns。为了以非破坏性的和有效的方法来管理接近表面层状态的CdTe,在T=80 K下进行了光致发光实验。为了监测熔化阈值,研究了由Acrorad公司制造和抛光的尺寸为5 mm×5 mm×0.5 mm的Cl补偿p-CdTe(111)单晶的光致发光光谱。经过研究发现,在激光脉冲寿命从7ns到1μs的范围内,CdTe熔化阈值明显取决于光吸收系数α(λ)。因为在脉冲寿命长于1μs的情况下,热扩散深度明显大于CdTe中的激光辐射穿透深度,并开始依赖于反射系数R(λ)。对于较短的激光脉冲长度τ_(p),当辐射波长λ变化时,熔化阈值会发生显著变化。同时,非平衡过剩载流子参数的变化(如表面重组速度S从10^(3)m/s增加到10^(5)m/s,还有扩散深度LD从0.4μm增加到2μm)会对CdTe熔化阈值产生至少25%的影响。而且红宝石激光的脉冲持续时间在(20±5)ns区间内的变化导致相对熔化阈值的变化(ΔIth/Ith)为35%。CdTe熔化阈值的计算值可以有效地被用于优化脉冲激光对晶体的表面处理与掺杂。

关键词：碲化镉熔化阈值脉冲激光辐照半导体激光掺杂

Mesoscopic Models of Plants Composed of Metallic Nanowires

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 Bionic Engineering 2013年第3期10卷 368-376页

作者： Galina K. Strukova Gennady v. Strukov Evgeniya Yu. Postnova alexander Yu. Rusanov Ivan S. veshchunov Institute of Solid State Physics Russian Academy of Sciences 142432 Chernogolovka Russia

various metallic structures of complex shape resembling living plant organisms （biomimetics） are produced as a result of self-assembly of nanowires growing on porous membranes in the course of pulse current electrodeposition. These structures occur if the electroplating is continued after the nanowires appear on the membrane surface. By varying the membrane ge- ometry, pulse current electroplating parameters, and alternating electrodeposition from two baths composed of a variety of electrolytes, diverse models were fabricated, including a hollow container with a wall thickness of 10 nm 20 nm. This biomimetic method suggests an analogy between the shape-forming processes of plants and their metallic models. Nanostruc- tured mesostructures of various metals （Ag, Pd, Ni）, alloys （PdNi, Pbln） and hybrid structures .（PdNi/Pb, PdNi/Pbln） were obtained. They can be of interest for fundamental research （self-assembly, morphogenesis） as well as for applications in nanotechnology （catalysis, nanoplasmonics, medicine, superhydrophobic surfaces）.

关键词： templated growth pulse electroplating self-assembly metallic mesostructures nanowires fractal branching biomimetic method

In vivo assessment of structural changes of the urethra in lower urinary tract disease using cross-polarization optical coherence tomography

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 Innovative Optical Health Sciences 2020年第6期3卷 55-70页

作者： Elena B.Kiseleva alexander A.Moiseev Anton S.Kuyarov Muhammat A.Molvi Grigory v.Gelikonov Anna v.Maslennikova Olga S.Streltsova Privolzhsky Research Medical University 10/1 Minin and Pozharsky Square 603005 Nizhny NovgorodRussia Institute of Applied Physics Russian Academy of Sciences Ulyanova Street 46603950Nizhny NovgorodRussia

The paper presents the results of a study of the female urethra in cases of urethral pain syndrome(UPS)and inflammatory diseases of the lower urinary tract using cross-polarization optical coherence tomography(CP OCT).Urethral wall structure was studied in 86 patients;233 CP OCT images were collected.A comparative qualitative analysis of three groups of CP OCT images—"norm","Inflammation"and"UPS"—identified that despite the absence of a clear inflammatory factor in the patient's examination,the urethral tissues in UPS were in an altered *** changes in the urethral wall with UPS and in cases of inflammation were *** a point scale,three experts independently performed visual scoring of the CP OCT *** parameters:epithelial contrast,cavities and the minimum signal depth in the co-channel were *** was found that,individually,the parameters correlate only weakly with the *** under the receiver operating characteristic(ROC)curve was from 0.51 to *** joint use of a number of visual signs has a greater diagnostic value than the use of the criteria *** under the ROC curve using the developed cumulative criterion reached up to *** study could form the basis of a scoring system for assessing the state of the urethral tract using CP OCT images in real *** CP OCT method provides information on the state of urethral tissues that cannot be obtained with traditional cystoscopy.

关键词： Cross-polarization optical coherence tomography urethral pain syndrome connective tissue visual analysis of images automatic classification of images

Diclofenac sodium aqueous systems at low concentrations: Interconnection between physicochemical properties and action on hydrobionts

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 Environmental Sciences 2020年第2期32卷 177-186页

作者： Irina S.Ryzhkina Yuliya v.Kiseleva Lyaisan I.Murtazina Tatyana v.Kuznetsova Erik R.Zainulgabidinov Igor v.Knyazev Andrew M.Petrov Sergey E.Kondakov alexander I.Konovalov Arbuzov Institute of Organic and Physical Chemistry FRC Kazan Scientific CenterRussian Academy of Sciences8 Arbuzov str.Kazan 420088Russia Institute for Problems of Ecology and Mineral Wealth Use of Tatarstan Academy of Sciences 28 Daurskaya Str.Kazan 420087Russia Lomonosov Moscow State University Chemistry Dept.1/3 Lenin HillsMoscow 119899Russia

Diclofenac sodium(DS) is a widely used nonsteroidal anti-inflammatory drug(NSAIDs).NSAIDs are poorly removed during standard wastewater *** consequences of the presence of NSAIDs in rivers and lakes at 10-11–10-8 mol/L are not yet established;therefore, ecotoxicologists have focused their efforts on studying the effect of lowconcentration NSAIDs on fish and hydrobionts, and also on predicting the potential risks to *** provides some information about the bioeffects of some NSAID solutions in low concentrations but there is no physicochemical explanation for these *** the physicochemical patterns of DS solutions in the low range of concentrations and establishing an interconnection between the solutions’ physicochemical properties and bioeffects can provide a conceptually new and important source of information regarding the unknown effects of *** physicochemical properties and action of DS solutions on Ceriodaphnia affinis cladocerans,Paramecium caudatum infusoria, Chlorella vulgaris unicellular green algae, as well as on the growth of the roots of Triticum vulgare wheat seeds, were studied in the calculated concentration range of 1 × 10-3–1 × 10-18 mol/*** relationship between these phenomena was established using the certified procedures for monitoring the toxicity of natural water and *** was shown for the first time that water solutions of DS are dispersed systems in which the dispersed phase undergoes a rearrangement with dilution, accompanied by changes in its size and properties, which affects the nonmonotonic dependences of the system’s physicochemical properties and could cause nonmonotonic changes in action on hydrobionts in the low concentration range.

关键词： Diclofenac sodium Low concentration Aqueous solutions Physicochemical properties Hydrobionts Toxicity

Lakes of the Jom-Bolok volcanoes valley in the East Sayan Mts., Baikal region: Morphogenesis and potential for regional paleoenvironmental studies

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2019年第11期29卷 1823-1840页

作者： alexander SHCHETNIKOv Elena v. BEZRUKOvA Institute of the Earth’s Crust SB Russian Academy of Sciences Irkutsk 664033Russia vinogradov Institute of Geochemistry SB Russian Academy of Sciences Irkutsk 664033Russia Irkutsk State University Irkutsk 664033Russia Institute of Archaeology and Ethnography SB Russian Academy of Sciences Novosibirsk 630090Russia

This article describes the lake basins of the Jom-Bolok volcanic region in the East Sayan (the largest manifestation of the Holocene eruptions in Central Asia).The geomorphological position,origins,aspects of the structure and development are reviewed considering its sedimentary *** limnic morphogenesis here develops under the conditions of contrasting relief,high energy of neotectonic and exogenous *** established that Lake Khara-Nur,formed as a result of lava-damming of the Jom-Bolok river valley,emerged in its present form approximately 6500 years ago.A complex record on the environment and climatic changes,acquired from its sediments,made it possible to determine for the first time in this region the long-term trends in the development of the Middle and Late Holocene mountain geosystems and also the distinction of several paleogeographic stages of the formation of the natural *** average geochemical record resolution for the bottom sediments of the lake was made uniquely for the East Siberian lake records and is equal to 35 years,while the palynological record approximates 110 years.

关键词： lake morphogenesis Holocene volcanism lava-dammed lakes environmental change

Characterization and Electrochemical Properties of Nanostructured Zr-Doped Anatase TiO_2 Tubes Synthesized by Sol–Gel Template Route

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2017年第6期33卷 527-534页

作者： Denis P.Opra Sergey v.Gnedenkov Sergey L.Sinebryukhov Elena I.voit alexander A.Sokolov Evgeny B.Modin Anatoly B.Podgorbunsky Yury v.Sushkov veniamin v.Zheleznov Institute of Chemistry Far Eastern Branch of Russian Academy of Sciences Far Eastern Federal University National Research Centre "Kurchatov Institute"

A series of nanostructured Zr-doped anatase TiO_2 tubes with the Zr/Ti molar ratio of 0.01, 0.02, 0.03, and0.09 were prepared by a sol–gel technology on a carbon fiber template. The electrochemical performance of Zr-doped anatase TiO_2 as anodes for rechargeable lithium batteries was investigated and compared with undoped titania. Tests represented that after 35-fold charge/discharge cycling at C/10 the reversible capacity of Zr-doped titania（Zr/Ti = 0.03） reaches 135 m A h g^（-1）, while the capacity of undoped titania（Zr/Ti = 0） yielded only 50 m A h g^（-1）. Based on the results of the physicochemical investigation, three reasons of improving electrochemical performance of Zr-doped titania were suggested. According to the scanning electron microscopy and transmission electron microscopy, Zr^（4＋） doping induces a decrease in nanoparticle size, which facilitates the Li＋diffusion. The Raman investigations show the more open structure of Zr-doped TiO_2 as compared to undoped titania due to changing of the unit cell parameters, that significantly affects on the reversibility of the insertion/extraction process. The electrochemical impedance spectroscopy results indicate that substitution of Zr^（4＋） for Ti^（4＋） into anatase TiO_2 has favorable effects on the conductivity.

关键词： Li-ion batteries Anatase titania Nanostructured materials Sol–gel template process Doping Electrochemical performance

Forces of RBC interaction with single endothelial cells in stationary conditions:Measurements with laser tweezers

在线全文

学校读者我要写书评

暂无评论

Journal of Innovative Optical Health Sciences 2021年第5期4卷 53-63页

作者： Arseniy A.Kapkov Alexey N.Semenov Petr B.Ermolinskiy Andrei E.Lugovtsov alexander v.Priezzhev Faculty of Physics Lomonosov Moscow State UniversityLeninskie GoryMoscow 119991Russia Faculty of Biology Lomonosov Moscow State UniversityLeninskie GoryMoscow 119991Russia

Red blood cells(RBCs)are able to interact and communicate with endothelial cells(ECs).Under some pathological or even normal conditions,the adhesion of RBCs to the endothelium can be ***,the mechanisms and many aspects of the interaction between RBCs and ECs are not fully *** this work,we considered the interaction of single RBCs with single ECs in vitro aiming to quantitatively determine the force of this interaction using laser *** were performed under different concentrations of proaggregant macromolecules and in the presence or absence of tumor necrosis factor(TNF-α)activating the *** have shown that the strength of interaction depends on the concentration of fibrinogen or dextran proaggregant macromolecules in the environment.A nonlinear increase in the force of cells interaction(from 0.4 pN to 21 pN)was observed along with an increase in the fibrinogen con-centration(from 3 mg/mL to 9 mg/mL)in blood plasma,as well as with the addition of dextran macromolecules(from 10 mg/mL to 60 mg/mL).Dextran with a higher molecular mass(500 kDa)enhances the adhesion of RBCs to ECs greater compared to the dextran with a lower molecular mass(70 kDa).With the preliminary activation of ECs with TNF-α,the force of interaction ***,the adhesion of echinocytes to EC compared to discocytes is significantly *** results may help to better understand the process of interaction between RBCs and ECs.

关键词： Endothelial cells red blood cells laser tweezers adhesion

PHOTOTHERAPY OF GINGIvITIS:PILOT CLINICAL STUDY

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 Innovative Optical Health Sciences 2011年第4期4卷 437-446页

作者： ELINA A.GENINA vLADIMIR A.TITORENKO vALERY v.TUCHIN GEORGY v.SIMONENKO ALEXEY N.BASHKATOv GENNADY M.SHUB alexander v.LEPILIN ILYA v.YAROSLAvSKY GREGORY B.ALTSHULER Saratov State University Saratov410012Russia Saratov State Medical University Saratov410012Russia Institute of Precise Mechanics and Control of RAS Saratov 410028Russia Palomar Medical Technology Inc.Burlington MA 01803USA

The goal of this work was to evaluate the safety and efficacy of the Red Light Emitted Toothbrush(R-LETB)emitting at wavelength of 663 nm with power density of 3.3mW/cm2 in combination with 0.1%-methylene blue(MB)solution for the reduction of plaque and treatment of gingivitis.A microbiological in vitro study and a pilot clinical study were *** microbiological study has shown total suppression of pathogenicflora after a 3-min exposure to the dye solution followed by a 20-sec treatment with the *** the clinical study,37 subjects of both sexes with gingivitis were enrolled and randomly assigned to one of two *** in thefirst(treatment)group were instructed to rinse their mouth with MB solution provided for 1 min and then brush the teeth with the R-LETB and standardized *** second(control)group used only the toothpaste and a regular *** in both groups followed their respective procedures 2 times a day(morning and evening)for 30 *** of plaque,gingival bleeding,and inflammation were evaluated at 14-day and 30-day *** the both groups,all indices improved in comparison with ***,the treatment group demonstrated more pronounced improvement of the studied indices that was attributed to additional anti-microbial action of red light and MB on gum ***,the use of R-LETB with MB appears to have a multifactor therapeutic action on oral pathological microflora:mechanical removal of the bacteria and suppressing action on microorganisms due to photodynamic reaction.

关键词： Tooth brushing methylene blue photodynamic therapy pathogenic bacteria

Online search tool for graphical patterns in electronic band structures

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2018年第1期4卷 272-279页

作者： Stanislav S.Borysov Bart Olsthoorn M.Berk Gedik R.Matthias Geilhufe alexander v.Balatsky Nordita KTH Royal Institute of Technology and Stockholm UniversityRoslagstullsbacken 23SE-10691 StockholmSweden Department of Physics Stockholm UniversitySE-10691 StockholmSweden Department of Computer Science KTH Royal Institute of TechnologySE-10044 StockholmSweden Department of Physics University of ConnecticutStorrsCT 06269USA Department of Management Engineering Technical University of DenmarkDTU2800 Kgs.LyngbyDenmark

Many functional materials can be characterized by a specific pattern in their electronic band structure,for example,Dirac materials,characterized by a linear crossing of bands;topological insulators,characterized by a“Mexican hat”pattern or an effectively free electron gas,characterized by a parabolic *** find material realizations of these features,manual inspection of electronic band structures represents a relatively easy task for a small number of ***,the growing amount of data contained within modern electronic band structure databases makes this approach *** address this problem,we present an automatic graphical pattern search tool implemented for the electronic band structures contained within the Organic Materials *** tool is capable of finding user-specified graphical patterns in the collection of thousands of band structures from high-throughput calculations in the online *** this tool,it only takes a few seconds to find an arbitrary graphical pattern within the ten electronic bands near the Fermi level for 26,739 organic *** source code of the developed tool is freely available and can be adapted to any other electronic band structure database.

关键词： graphical electronic bands