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Photoisomerization of norbornadiene group in a rigid bichromophoric compound initiated by remote keto chromophore: long-distance through-bond triplet energy transfer

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chinese Journal of chemistry 1996年第4期14卷 377-380页

作者： Tung, ch Zhang, LP Li, Y chINESE ACAD SCI INST PHOTOG CHEMBEIJING 100101PEOPLES R CHINA

A diad compound 3 beta(bicyclo[2,2,1]hepta-2,5-diene-2-methylcarboxylate-3-carboxy)-androst-5-en-17-one (NBD-S-ONE) was synthesized and its photochemistry was examined. Irradiation of NBD-S-ONE in acetonitrile at lambda > 300 nm selectively excited the keto chromophore. After intersystem crossing, the triplet energy of the keto group was transferred to the NBD group with 18.6% efficiency via a through-bond mechanism, resulting in the isomerization of the latter group to the quadricyclane group.

关键词： norbornadiene photoisomerization through-bond triplet energy transfer

Synthesis and Spectrophotometric Studies of 2-(5-Carboxy-1,3,4-triazolylazo)-5-diethylamino Aniline

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chinese chemical Letters 2000年第10期11卷 861-862页

作者： Pan, FY Ge, ch Liang, HD Taizhou Teachers Coll Dept Chem Zhejiang 317000 Peoples R China

In this paper, 2-(5-carboxy-1,3,4-triazolylazo)-5-diethylamino aniline(CTZAN) was prepared the protonation behaviour of this reagent is reported. Its structure was identified.

关键词： synthesis triazolylazo spectrophotometry protonation behaviour

Development of open-porosity magnesium foam produced by investment casting

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Journal of Magnesium and Alloys 2022年第7期10卷 1941-1956页

作者： Honorata Kapłon Carsten Blawert Jacek ch˛ecmanowski Krzysztof Naplocha Faculty of Mechanical Engineering Wrocław University of Science and TechnologyUl.Smoluchowskiego 25Wrocław 50-370Poland Institute of Surface Science Helmholtz-Zentrum GeesthachtMax-Planck-Straβe 1Geesthacht21502Germany Faculty of chemistry Wrocław University of Science and TechnologyWybrze˙ze Stanisława Wyspia´nskiego 27Wrocław50-370Poland

High-porosity,open-cell AZ91 magnesium alloy foams of two pore sizes were fabricated by means of investment casting technology,using PUR foam *** casting variables such as pressure,mould temperature and metal pouring temperature were thoroughly investigated to define the most optimal casting *** mechanical properties of the fabricated foams were measured in compression tests.A potential application for the foams considered is temporary bioresorbable bone implants,therefore the mechanical properties of the foams were compared with those of cancellous bone *** with smaller pore size and lower porosity(20 PPI and 80%±87%)exhibited mechanical properties in the lower regions of the cancellous bone property range(Young’s modulus 36.5±77.5 MPa),while foams with higher pore size and porosity(10 PPI and~90%)were found to have insufficient compression strength(Young’s modulus 11.65±23.8),but thickening their walls and lowering their porosity below 90%yielded foams with Young’s modulus between 36.5 and 77.5 *** fractures were also investigated to determine their collapse mechanism.A series of corrosion tests in stimulated body fluid was carried out to determine their applicability as a *** Plasma Electrolytic Oxidation(PEO)process was used in a feasibility study to examine the microstructure and chemical composition of foams with protective coating.

关键词： Magnesium foams AZ91 investment casting Bone implants Plasma electrolytic oxidation

Geochemical studies of hybrid granite from Madugulapalli area, Eastern Dharwar Craton, Southern India: Implications for crustal mixing

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Acta Geochimica 2023年第1期42卷 9-23页

作者： Nagamma J Ratnakar J Ajay kumar A Ashok ch State Mines and Geology Department 508001 NalgondaIndia Department of Geology Osmania University500007 HyderabadIndia CSIR-National Geophysical Research Institute 500007 UppalHyderabadIndia

Magma produced by melting of continental crust and mantle at the Archean-Proterozoic boundary are compositionally variable and chemical compositions provide evidence for the mixing of two sources. Understanding the composition of hybrid magma is essential for determining the comparative infl uence of crust and mantle sources during orogenesis. The hybrid granites are less documented in Indian cratons, especially less in Dharwar Craton. Here we present petrographic and whole-rock geochemical data of Madgulapalli granitic rocks situated in the NE part of the Eastern Dharwar Craton(EDC), to elucidate their petrogenesis and role in crust formation. The Madugulapalli granites(MPG) are composed chiefl y of plagioclase, quartz, and alkali feldspar with associated biotite showing alteration and inter-granular textures. Geochemically, they are metaluminous to peraluminous in nature with calc-alkaline hybrid granite. The hybrid granites exhibit both negative and positive europium anomalies;the lower Rb/Sr, Rb, Sr, and higher Sr/Y,(Dy/Yb)N ratios suggest that the interaction of older rocks with residual garnet source melted at high pressures. We hypothesize that hybrid granites are formed by interaction(e.g., metasomatism, mingling, or mixing) between parental magmas and pre-existing rocks with the infl uence of sanukitoid melts(heat source) in a subduction environment. The genesis of the hybrid granites demonstrates the mixing coupled with diff erentiation in the petrogeny’s residue system in a syn-collision setting followed by continental crust stability in EDC during the Neoarchean period.

关键词： Madugulapalli granite Hybrid granite Crustal mixing Subduction

Predicting invasion potential of Senna didymobotrya (Fresen.) Irwin & Barneby under the changing climate in Africa

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Ecological Processes 2021年第1期10卷 89-98页

作者： Elias ch.Weldemariam Dejene Sintayehu W. Department of Geo-information Science Haramaya UniversityDire DawaEthiopia College of Agriculture and Environmental Sciences Haramaya UniversityDire DawaEthiopia

Background:Senna didymobotrya is a native African flowering *** is suspected that climate change encourages the introduction and spread of invasive alien *** possible invasion of *** across the continent is expected to increase in the future due to ongoing climate ***,there is still paucity of empirical evidence on the extent to which the changing climate contributes to the surge of the flowering *** study,therefore,investigated the present and potential invasion of *** using the species distribution model under changing climate *** two representative concentration pathways(RCP4.5 and RCP8.5)and eight bioclimatic variables and one topographic variable were used to simulate the current and future(2050s and 2070s)invasion of *** in *** model performance was assessed using the area under the receiver operating characteristic curve(AUC)and true skill statistics(TSS).Results:The results of the study showed that under the current climatic conditions,18%of Africa is suitable for the establishment and invasion of *** most suitable hotspot for *** invasion is eastern Africa,followed by southern *** predicted model showed that by 2050,3.3%and 3.12%of the continent would be highly suitable areas for the invasion of the species under RCP4.5 and RCP8.5,*** the 2070s,under RCP4.5 and RCP8.5,the highly suitable area would be 3.13%and 2.7%,*** relation to the current suitability,the cumulative projected areas of the low and moderate suitability class under RCP4.5 and RCP8.5 will rise by the years 2050 and ***,under both RCPs,the non-suitable area for *** invasion would gradually ***:From the findings,it can be concluded that the ecosystem’s vulnerability to *** invasion under future climatic conditions will proliferate ***,to prevent the projected harm to biodiversity and ecosys

关键词： Senna didymobotrya Invasive species Climate change Africa Ensemble approach

RATIONAL GENERAL SOLUTIONS OF HIGHER ORDER ALGEBRAIC ODES

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Journal of Systems Science & Complexity 2013年第2期26卷 261-280页

作者： HUANG Yanli NG L X chu WINKLER Franz School of Computer Science and Software Engineering Tianjin Polytechnic University Research Institute for Symbolic Computation(RISC) Johannes Kepler University Department of Mathematics Quy Nhon University

This paper generalizes the method of Ng6 and Winkler （2010, 2011） for finding rational general solutions of a first order non-autonomous algebraic ordinary differential equation （AODE） to the case of a higher order AODE, provided a proper parametrization of its solution hypersurface. The authors reduce the problem of finding the rational general solution of a higher order AODE to finding the rational general solution of an associated system. The rational general solutions of the original AODE and its associated system are in computable 1-1 correspondence. The authors give necessary and sufficient conditions for the associated system to have a rational solution based on proper reparametrization of invariant algebraic space curves. The authors also relate invariant space curves to first integrals and characterize rationally solvable systems by rational first integrals.

关键词： Algebraic ODE associated system invariant algebraic space curve rational first integral rational general solution.

Effect of Diffuser Vane Shape on the Performance of a Centrifugal Compressor Stage

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Journal of Thermal Science 2014年第2期23卷 127-132页

作者： T ch Siva Reddy GV Ramana Murty MVSSSM Prasad Sreenidhi Institute of Science and Technology GhatkesarHyderabadA.P.India Vasavi College of Engineering Hhyderabad

The present paper reports the results of experimental investigations on the effect of diffuser vane shape on the performance of a centrifugal compressor stage. These studies were conducted on the chosen stage having a back- ward curved impeller of 500 turn tip diameter and 24.5 mm width and its design flow coefficient is Фd=0.0535. Three different low solidity diffuser vane shapes namely uncarnbered aerofoil, constant thickness flat plate and circular arc cambered constant thickness plate were chosen as the variants for diffuser vane shape and all the three shapes have the same thickness to chord ratio （t/c=0.1）. Flow coefficient, polytropic efficiency, total head coeffi- cient, power coefficient and static pressure recovery coefficient were chosen as the parameters for evaluating the effect of diffuser vane shape on the stage performance. The results show that there is reasonable improvement in stage efficiency and total head coefficient with the use of the chosen diffuser vane shapes as compared to conven- tional vaneless diffuser. It is also noticed that the aero foil shaped LSD has shown better performance when com- pared to flat plate and circular arc profiles. The aerofoil vane shape of the diffuser blade is seen to be tolerant over a considerable range of incidence.

关键词： Centrifugal compressor Vaneless diffuser Low solidity diffuser

Effect of spark plasma sintering and reinforcements on the formation of ultra-fine and nanograins in AA2024-TiB2-Y hybrid composites

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Progress in Natural Science:Materials International 2022年第1期32卷 79-86页

作者： ch.Suresh Vidyasagar D.B.Karunakar Department of Architecture and Planning Indian Institute of Technology Roorkee Mechanical and Industrial Engineering Department Indian Institute of Technology Roorkee

This study reports the influence of sintering mechanism and reinforcement materials on the formation of ultra-fine and nanograins in Al-TiB-Y nanohybrid composites. The mechanical properties of the composites and their corresponding micro and nanostructures are correlated. The experimental and characterization results revealed that despite the addition of TiB, the hard and brittle AlTi phase formation in the composites was suppressed and hence, their ductility was retained. It was found that yttrium content of 0.3 wt% was the optimum amount which created advantageous spark plasma sintering conditions, and the addition of 0.3 wt% promoted the formation of bi-modal size grains（ultra-fine and nano） along with micro grains, Ω and other nano precipitates, resulting in a significant enhancement in the composite properties. The formation of ultra-fine and nanograins may be attributed to the combined effect of melting and rapid solidification at necking zones due to Joule’s heating and thermomechanical fatigue. Among all the sintered composites, the highest hardness（137 HV）, ultimate tensile strength（UTS）(496 MPa), yield strength（YS）(438 MPa) with 15.7% elongation were obtained in the sintered sample reinforced with 1.0 wt% TiBand 0.3 wt% yttrium.

关键词： Hybrid composites Ultra-fine grains Nano grains Spark plasma sintering Nano precipitates Microstructure

A Hyper-ellipsoid Model for Metallurgical Process Modelling by Genetic Algorithm

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Journal of Materials Science & Technology 1998年第6期14卷 567-568页

作者： Li, JF Li, ch chen, NY Lu, T chinese Acad Sci Shanghai Inst Met Shanghai 200050 Peoples R China Univ SW Louisiana Lafayette LA 70504 USA

A hyper-ellipsoid model, using genetic algorithm as method of computation, has been proposed to be used in certain metallurgical processes. It is especially suitable for the modelling of the metallurgical processes wi... 详细信息

关键词： Metallurgy