检索结果-南通市图书馆

Why lowland riparian trees are difficult to use for streamflow reconstruction

Journal of Forestry Research 2024年第3期35卷 219-230页

作者： Xiaomei Peng Shengchun Xiao Bao Yang Quanyan Tian vladimir V.Shishov Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000People's Republic of China School of Geography and Ocean Science Nanjing UniversityNanjing 210023People's Republic of China Institute of Fundamental Biology and Biotechnology Siberian Federal UniversityKrasnoyarskRussia 660041

Existing streamflow reconstructions based on tree-ring analysis mostly rely on species from upland,mainly montane areas,while lowland species(generally plain)areas are rarely *** limits the understanding of streamflow change history in the lowlands,which is an important basis for water resource *** study focused on Populus euphratica stands located along the main stream,eastern and western tributaries in the lower reaches of the Heihe River basin(HRb),in arid northwestern *** investigated how streamflow regulation interferes with ripar-ian trees in lowlands when they used for streamflow ***-ring width chronologies were developed and analyzed in conjunction with meteorological and hydrologic observation *** results show streamflow regulation leads in sharp fluctuations in the streamflow allocation between the eastern tributaries and western *** resulted in instability of the correlation between streamflow at the two tributaries and at the Zhengyixia hydrologic station,with corresponding fluctuations in radial growth of poplar trees on the banks of the two tributaries and at the *** regulation altered the natural patterns of seasonal streamflow below the station,changing the time window of poplar *** study provides useful insight into tree-ring width based streamflow reconstruction in the lowlands.

关键词： Tree-ring width-Dendrochronology Populus euphratica The Ejina Oasis Streamflow

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Significance of balloon aortic valvuloplasty as palliative procedure for symptom benefit in patients with severe aortic stenosis

引用

Journal of Geriatric Cardiology 2024年第3期21卷 374-378页

作者： Jovica Banovic vladimir Djuric Vojislav Vuksinovic Sasa Loncar Department of Internal Medicine/Prijedor Republic of SrpskaBosnia and Herzegovina University Clinical Centre of Republic of Srpska Cardiology ClinicBanja LukaRepublic of SrpskaBosnia and Herzegovina

Aortic stenosis(AS)stands out as the most prevalent individual valvular defect *** onset and progression of AS mirror an active process akin to atherosclerosis,and the traditional triad of symptoms includes chest pain,breathlessness,and loss of *** takes a significant downturn when symptoms manifest,with mortality reaching approximately 50%-85% within the subsequent 5 years after symptom onset.

关键词： balloon stenosis mortality

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Influence of Methane-Hydrogen Mixture Characteristics on Compressor Vibrations

引用

Fluid Dynamics & Materials Processing 2024年第5期20卷 1031-1043页

作者： vladimir Ya.Modorskii Ivan E.Cherepanov High Performance Computing Center Perm National Research Polytechnic UniversityPerm614990Russia

A transition to clean hydrogen energy will not be possible until the issues related to its production, transportation,storage, etc., are adequately resolved. Currently, however, it is possible to use methane-hydrogen *** gas can be transported using a pipeline system with the required pressure being maintained by gascompression stations. This method, however, is affected by some problems too. Compressors emergency stopscan be induced by vibrations because in some cases, mechanical methods are not able to reduce the vibrationamplitude. As an example, it is known that a gas-dynamic flow effect in labyrinth seals can lead to increasedvibrations. This paper presents the numerical simulation of rotor oscillations taking into account a gas-dynamicload. The influence of a transported mixture on the oscillatory process is investigated. Mixtures consisting ofmethane and hydrogen in various proportions and an air mixture are considered. The results are discussed forvarious operating pressures and include the rotor motion trajectories and oscillation frequency spectra obtainednumerically. It is shown that the gas mixture composition has a significant effect on the oscillations and theiroccurrence. Hydrogen as a working fluid reduces the vibration amplitude. Operating a compressor with hydrogenleads to a decrease in the resonant frequency, bringing it closer to the operating one. However, the operatingpressure at which maximum oscillations are observed depends slightly on the gas mixture composition.

关键词： Seal stabilities vibration FSI CFD multiphase flows hydrogen

来源：

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

Target acquisition performance in the presence of JPEG image compression

引用

Defence Technology（防务技术） 2024年第3期33卷 30-41页

作者： Boban Bondzulic Nenad Stojanovic vladimir Lukin Sergey A.Stankevich Dimitrije Bujakovic Sergii Kryvenko University of Defence in Belgrade Military AcademyVeljka Lukica Kurjaka 3311000 BelgradeSerbia National Aerospace University Department of Information-Communication TechnologiesChkalova 1761070 KharkivUkraine National Academy of Sciences of Ukraine Scientific Centre for Aerospace Research of the EarthOles Honchar 55-b01054 KyivUkraine

This paper presents an investigation on the effect of JPEG compression on the similarity between the target image and the background,where the similarity is further used to determine the degree of clutter in the *** new clutter metrics based on image quality assessment are introduced,among which the Haar wavelet-based perceptual similarity index,known as HaarPSI,provides the best target acquisition prediction *** is shown that the similarity between the target and the background at the boundary between visually lossless and visually lossy compression does not change significantly compared to the case when an uncompressed image is *** future work,through subjective tests,it is necessary to check whether this presence of compression at the threshold of just noticeable differences will affect the human target acquisition *** values are compared with the results of subjective tests of the well-known target Search_2 database,where the degree of agreement between objective and subjective scores,measured through linear correlation,reached a value of 90%.

关键词： JPEG compression Target acquisition performance Image quality assessment Just noticeable difference Probability of target detection Target mean searching time

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Superior piezoelectric performance with high operating temperature in bismuth ferrite-based ternary ceramics

引用

Journal of Materials Science & Technology 2024年第2期169卷 172-181页

作者： Yunyao Huang Leiyang Zhang Ruiyi Jing Yang Yang vladimir Shur Xiaoyong Wei Li Jin Electronic Materials Research Laboratory Key Laboratory of the Ministry of EducationSchool of Electronic Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China Faculty of Materials and Manufacturing Key Laboratory of Advanced Functional MaterialsEducation Ministry of ChinaBeijing University of TechnologyBeijing 100124China School of Natural Sciences and Mathematics Ural Federal UniversityEkaterinburg620000Russia

Due to the thermal depolarization effect,adequate piezoelectric performance with high operating temperature is regarded to be challenging to accomplish concurrently in piezoceramics for applications in specific piezoelectric *** this work,we synthesized(0.8−x)BiFeO_(3)-x PbTi_(3)-0.2Ba(Zr_(0.25)Ti_(0.75))O_(3)(abbreviated as BFO-x PT-BZT)ternary solid solutions with 0.15≤x≤0.30 by conventional solid-state reaction *** MPB composition with a coexisting state of rhombohedral-tetragonal phases exhibits enhanced electromechanical properties,including Curie temperature of 380℃,large-signal equivalent piezoelectric coefficient d^(∗)_(33)of 395 pm V^(-1),small-signal piezoelectric coefficient d_(33)of 302 pC N^(-1),and electromechanical coupling factor k_(p)of 50.2%,which is comparable to commercial PZT-5A ceramics,indicating potential in high-temperature ***,in-situ X-ray diffraction(XRD)and piezoelectric force microscopic(PFM)techniques demonstrate that multiphase coexistence and complex nanodomains promote piezoelectric response via *** x=0.24 composition exhibits the highest in-situ d_(33)of 577 pC N^(-1)and good temperature stability in 30−280℃,indicating that BZT-modified BFO-PT ceramics are promising candidates for high-temperature piezoelectric devices.

关键词： High-temperature piezoelectrics Morphotropic phase boundary In-situ technique Domain structure BFO

来源：

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

Physico−mathematical model of the voltage−current characteristics of light-emitting diodes with quantum wells based on the Sah−Noyce−Shockley recombination mechanism

引用

Journal of Semiconductors 2024年第8期45卷 25-33页

作者： Fedor I.Manyakhin Dmitry O.Varlamov vladimir P.Krylov Lyudmila O.Morketsova Arkady A.Skvortsov vladimir K.Nikolaev Dinamics Strength of Machines and Resisance of MaterialsMoscow Polytechnic UniversityRussia Biomedical and Electronic Means and Technologies Vladimir State UniversityRussia Computer-Aided Design and Engineering National University of Science and Technology"MISiS"Russia

Herein,a physical and mathematical model of the voltage−current characteristics of a p−n heterostructure with quantum wells(QWs)is prepared using the Sah−Noyce−Shockley(SNS)recombination mechanism to show the SNS recombination rate of the correction function of the distribution of QWs in the space charge region of diode configuration.A comparison of the model voltage−current characteristics(VCCs)with the experimental ones reveals their *** technological parameters of the structure of the VCC model are determined experimentally using a nondestructive capacitive approach for determining the impurity distribution profile in the active region of the diode structure with a profile depth resolution of up to 10Å.The correction function in the expression of the recombination rate shows the possibility of determining the derivative of the VCCs of structures with QWs with a nonideality factor of up to 4.

关键词： light-emitting diodes with quantum wells voltage−current relation nonideality factor recombination mechanism Sah−Noyce−Shockley model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Technological parameters of thin-film pulsed laser scribing for perovskite photovoltaics

引用

CLEAN ENERGY 2024年第3期8卷 127-135页

作者： Ishteev, Rustam Gostishchev, Pavel Tiukhova, Mariia Sorokin, Anton Ishteev, Arthur Kondratenko, vladimir RTU MIREA Inst Adv Technol & Ind Programming Dept Nanoelect Lab Precis Machining Mat Moscow Russia Res & Pract Clin Ctr Diagnost & Telemed Technol Moscow Hlth Care Dept Moscow Russia Natl Univ Sci & Technol MISIS Lab Adv Solar Energy LASE 4 Leninsky St Moscow Russia Russian Acad Sci RAS Semenov Fed Res Ctr Chem Phys 4 Kosygina Str Moscow Russia

Over the past decade, the power conversion efficiency of halide perovskite solar cells has shown a rapid increase to 26.1%. The significant efficiency growth and the relative simplification of the technology for obtaining thin-film solar cells due to liquid printing methods determine the high potential for the low-cost perovskite solar cells manufacturing. However, efficient use of cell geometry is comparable to the size of standard crystalline-Si wafers (156:156 mm and more). Therefore, modular geometry similar to amorphous-Si solar cell approaches is used to scale perovskite solar cells. Serial electrical connection of thin-film cells requires precise processing of the conductive layers that form the device p-i-n structure. The subject of research is the development of a full pulsed laser scribing cycle for inverted perovskite solar cells. In this work, we propose a study of a laser-patterning technology In2O3:SnO2 (ITO) conductive layer and a photoactive perovskite layer Cs0,2(CH(NH2)2)0,8PbI3. Process regimes of transparent conducting electrodes based on ITO and halide perovskite layer Cs0,2(CH(NH2)2)0,8PbI3 laser patterning were obtained. The optimal parameters for the multipass mode processing of ITO and perovskite layer were determined. The cell was electrically isolated at a scribe line width of 30 mu m. A full pulsed-laser scribing cycle for inverted perovskite solar cells is developed and applied to laser-patterning of an indium-tin oxide (ITO) conductive layer and a photoactive perovskite layer. The optimal parameters for the multipass mode processing of ITO and perovskite layers are determined. Graphical Abstract

关键词： patterning perovskite solar cell perovskite solar cell photovoltaics scribing SOLAR MODULES CELLS

来源：

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

Long-term Speckle Interferometric Monitoring of Binary Systems:2007–2023Positional Measurements and Orbits of Seven Objects

引用

Research in Astronomy and Astrophysics 2024年第9期24卷 147-155页

作者： Arina Mitrofanova vladimir Dyachenko Anatoly Beskakotov Yuri Balega Alexander Maksimov Denis Rastegaev Special Astrophysical Observatory 369167 Nizhnij ArkhyzRussia

The results of seventeen years of speckle interferometric monitoring of seven objects(Chara 122Aa,GJ 3010,HIP1987,GJ 3076,HIP 11253,HIP 11352,and HIP 14929)are *** data were obtained at the 6 m Big Telescope Alt-azimuthal Special Astrophysical Observatory of the Russian Academy of Science(BTA SAO RAS)from 2007 to the *** of previously published and new measurements made it possible to construct completely new orbits for Chara 122Aa,HIP 11253,and HIP *** orbit of GJ 3076 cannot be constructed accurately due to the large influence of the weights assigned to the *** resulting orbital solutions are classified based on a grading scheme suggested by ***,*** and ***;most orbits are“definitive”(Grade 1).The mass sums and masses of components calculated by two independent methods using Hipparcos and Gaia DR2 and DR3 parallaxes were compared for the objects under study.

关键词： techniques:high angular resolution (stars:)binaries:visual stars:fundamental parameters stars:low-mass stars:solar-type

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Bio-Based Rigid Polyurethane Foams for Cryogenic Insulation

引用

Journal of Renewable Materials 2024年第3期12卷 585-602页

作者： Laima Vevere Beatrise Sture vladimir Yakushin Mikelis Kirpluks Ugis Cabulis Latvian State Institute of Wood Chemistry RigaLV-1006Latvia

Cryogenic insulation material rigid polyurethane(PU)foams were developed using bio-based and recycled *** obtained from tall oil fatty acids produced as a side stream of wood biomass pulping and recycled polyethylene terephthalate were used to develop rigid PU foam *** 4th generation physical blowing agents with low global warming potential and low ozone depletion potential were used to develop rigid PU foam cryogenic insulation with excellent mechanical and thermal *** rigid PU foams had a thermal conductivity coefficient as low as 0.0171 W/m·K and an apparent density of 37-40 kg/m^(3).The developed rigid PU foams had anisotropic compression strength properties,which were higher parallel to the foaming ***,the compression strength was also influenced by the type of applied bio-based *** bio-based polyols with higher OH group functionality delivered higher crosslinking density of polymer matrix;thus,the mechanical properties were also *** mechanical strength of the foams increased when materials were tested at liquid nitrogen temperature due to the stiffening of the polymer *** thermal properties of the developed materials were determined using differential scanning calorimetry,dynamic mechanical analysis,and thermogravimetric analysis ***,the developed rigid PU foams had good adhesion to the aluminium substrate before and after applying cyroshock and an excellent safety coefficient of *** PU foams developed using Solstice LBA delivered adhesion strength of~0.5 MPa and may be considered for application as cryogenic insulation in the aerospace industry.

关键词： Cryogenic insulation polyurethanes tall oil 4th generation physical blowing agents

来源：

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

Arctic Sea Ice Variations in the First Half of the 20th Century:A New Reconstruction Based on Hydrometeorological Data

引用

Advances in Atmospheric Sciences 2024年第8期41卷 1483-1495,1686-1693页

作者： vladimir A.SEMENOV Tatiana A.ALDONINA Fei LI Noel Sebastian KEENLYSIDE Lin WANG A.M.Obukhov Institute of Atmospheric Physics RAS Moscow 119017Russia Institute of Geography RAS Moscow 119017Russia Geophysical Institute University of Bergen and Bjerknes Centre for Climate ResearchBergen 5007Norway Nansen Environmental and Remote Sensing Center Bergen 5007Norway Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

The shrinking Arctic sea-ice area(SIA) in recent decades is a striking manifestation of the ongoing climate *** of the Arctic sea ice have been continuously observed by satellites since 1979, relatively well monitored since the 1950s, but are highly uncertain in the earlier period due to a lack of observations. Several reconstructions of the historical gridded sea-ice concentration(SIC) data were recently presented based on synthesized regional sea-ice observations or by applying a hybrid model–empirical approach. Here, we present an SIC reconstruction for the period1901–2019 based on established co-variability between SIC and surface air temperature, sea surface temperature, and sea level pressure patterns. The reconstructed sea-ice data for March and September are compared to the frequently used Had ISST1.1 and SIBT1850 datasets. Our reconstruction shows a large decrease in SIA from the 1920 to 1940 concurrent with the Early 20th Century Warming event in the Arctic. Such a negative SIA anomaly is absent in Had ISST1.1 data. The amplitude of the SIA anomaly reaches about 0.8 mln km^(2) in March and 1.5 mln km^(2) in September. The anomaly is about three times stronger than that in the SIBT1850 dataset. The larger decrease in SIA in September is largely due to the stronger SIC reduction in the western sector of the Arctic Ocean in the 70°–80°N latitudinal zone. Our reconstruction provides gridded monthly data that can be used as boundary conditions for atmospheric reanalyses and model experiments to study the Arctic climate for the first half of the 20th century.

关键词： Arctic sea ice Arctic climate early 20th century warming climate variability

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：