检索结果-南通市图书馆

Mapping microstructure to shock-induced temperature fields using deep learning

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2023年第1期9卷 516-523页

作者： Chunyu Li juan Carlos verduzco Brian H.Lee Robert j.Appleton Alejandro Strachan School of Materials Engineering Purdue UniversityWest LafayetteIN 47907USA

The response of materials to shock loading is important to planetary science,aerospace engineering,and energetic materials.Thermally activated processes,including chemical reactions and phase transitions,are significantly accelerated by energy localization into hotspots.These result from the interaction of the shockwave with the materials’microstructure and are governed by complex,coupled processes,including the collapse of porosity,interfacial friction,and localized plastic deformation.These mechanisms are not fully understood and the lack of models limits our ability to predict shock to detonation transition from chemistry and microstructure alone.We demonstrate that deep learning can be used to predict the resulting shock-induced temperature fields in composite materials obtained from large-scale molecular dynamics simulations with the initial microstructure as the only input.The accuracy of the Microstructure-Informed Shock-induced Temperature net(MISTnet)model is higher than the current state of the art and its evaluation requires a fraction of the computation cost.

关键词： microstructure Microstructure friction

ON DIFFERENTIAL STRUCTURES OF POLYNOMIAL SPACES IN CONTROL THEORY

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

journal of Systems Science and Systems Engineering 2012年第3期21卷 372-382页

作者： Baltazar Aguirre HERNANDEZ Martn Eduardo FRIAS-ARMENTA Fernando verduzco Depto.de Matematicas Universidad Autonoma Metropolitana-lztapalapa.Av.Sn.Rafael Atlixco no.186.Col.Vicentinalztapalapa 09340MexicoD.F. Depto.de Matematicas Universidad de Sonora.Blvd.Luis Encinas y Rosales s/n.Col.CentroHermosilloSonoraMexico.

A valuable number of works has been published about Hurwitz and Schur polynomials in order to known better their properties. For example it is known that the sets of Hurwitz and Schur polynomials are open and no convex sets. Besides, the set of monic Schur polynomials is contractible. Now we study this set using ideas from differential topology, and we prove that the space of Schur complex polynomials with positive leading coefficient, and the space of Hurwitz complex polynomials which leading coefficient having positive real part, have structure of trivial vector bundle, and each space of （Schur complex and real, Hurwitz complex） polynomials has a differential structure diffeomorphic to some known spaces.

关键词： Schur polynomials Hurwitz complex polynomials trivial vector bundle

ZrCuAlNi系大块金属玻璃的非晶形成能力、热学和力学性能（英文）

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2018年第6期28卷 1157-1165页

作者： C.E.BORjA I.A.FIGUEROA O.LOZADA-FLORES M.ESTRADA G.A.LARA-RODRIGUEZ j.A.verduzco Instituto de Investigacion en Metalurgia y Materiales Universidad Michoacana de San Nicolfis de Hidalgo (UMSNH)Fco. J. Mujica S/N Col. Felicitas del Rio C.P. 58030 Morelia Mich. Mexico Instituto de Investigaciones en Materiales Universidad Nacional Autonoma de Mdxico (UNAM) Circuito Exterior S/N Cd. Universitaria C.P. 04510 Cd. Mx. Mexico

分析ZrCuAlNi系大块金属玻璃的非晶形成能力、热学和力学性能。运用密实堆积和动态脆性指数模型从理论上确定合金的成分。采用铜模吸铸法在氩气保护下制备圆柱形和圆锥形铸锭。用X射线衍射表征圆锥形铸锭以便确定非晶结构。结果表明:两... 详细信息

分析ZrCuAlNi系大块金属玻璃的非晶形成能力、热学和力学性能。运用密实堆积和动态脆性指数模型从理论上确定合金的成分。采用铜模吸铸法在氩气保护下制备圆柱形和圆锥形铸锭。用X射线衍射表征圆锥形铸锭以便确定非晶结构。结果表明:两种合金的临界非晶直径为3 mm。用差示扫描量热法(DSC)分析其热行为,加热速率分别为0.5、0.67和0.83 K/s。γ参数、过冷液相区ΔT_x和约化玻璃转变温度T_(rg)等这些实验所得的参数均表明其具有高的非晶形成能力。非晶成分显示其脆性指数为40。合金的压缩试验采用的应变速率为0.016 s^(-1),得到弹性模量约为83 GPa,总应变约为5%,屈服强度为1.6 GPa,硬度为4 GPa。运用密实堆积和动态脆性指数模拟可以预测ZrCuAlNi系合金的非晶形成成分。

关键词：大块金属玻璃非晶形成能力脆性指数堆积率吸铸

General and Exact Inbreeding Coefficient of Maize Synthetics Derived from Three-Way Line Hybrids

在线全文

学校读者我要写书评

暂无评论

Phyton-International journal of Experimental Botany 2022年第1期91卷 33-43页

作者： Alejandro Ibarra-Sánchez juan Enrique Rodríguez-Pérez Aureliano Peña-Lomelí Clemente Villanueva-verduzco jaime Sahagún-Castellanos Crop Science Department Chapingo Autonomus UniversityChapingo56230México

Synthetic varieties(SVs)are populations generated by randomly mating their parents.They are a good alternative for low-input farmers who grow onions,maize,and other allogamous crops since the seed produced by a SV does not change from one generation to the next.Although SV progenitors are commonly pure lines,in this case a synthetic(Syn_(TC))whose parents are t three-way line crosses,a very common type of maize hybrid grown in Mexico,is studied.The aim was to develop a general and exact equation for the inbreeding coefficient of a Syn_(TC)eF_(m)^(f)Syn_(TC)T because of its relationship with the mean of economically important traits.This objective arose due to the need for a more advanced study in terms of determining whether F_(m)^(f)Syn_(TC)can be applied specifically and accurately for any number of parents(t),plants per parent(m)and inbreeding coefficient(IC)of the initial lines(F_(L)).A formula for the IC of the Syn_(TC)was derived that,given any values of F_(L)(0≤F_(L)≤1)and t,is specific for any value of m,not just for“large”numbers associated with the context in which the Hardy-Weinberg law is stated.It was found that F_(m)^(f)Syn_(TC)is very sensitive to changes in m when m is not greater than eight,after which it tends to stabilize very quickly.In summary,unlike previously derived formulas,F_(m)^(f)Syn_(TC)is exact for any values of t,m and F_(L).

关键词： Genotypic array genotypic mean hybrid random mating Zea mays L

Indian plate paleogeography, subduction and horizontal underthrusting below Tibet: paradoxes, controversies and opportunities

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

National Science Review 2022年第8期9卷 175-193页

作者： Douwe j.j.van Hinsbergen Department of Earth Sciences Utrecht University

The India–Asia collision zone is the archetype to calibrate geological responses to continent–continent collision, but hosts a paradox: there is no orogen-wide geological record of oceanic subduction after initial collision around 60–55 Ma, yet thousands of kilometers of post-collisional subduction occurred before the arrival of unsubductable continental lithosphere that currently horizontally underlies Tibet. Kinematically restoring incipient horizontal underthrusting accurately predicts geologically estimated diachronous slab break-off, unlocking the Miocene of Himalaya–Tibet as a natural laboratory for unsubductable lithosphere convergence. Additionally, three endmember paleogeographic scenarios exist with different predictions for the nature of post-collisional subducted lithosphere but each is defended and challenged based on similar data types. This paper attempts at breaking through this impasse by identifying how the three paleogeographic scenarios each challenge paradigms in geodynamics, orogenesis, magmatism or paleogeographic reconstruction and identify opportunities for methodological advances in paleomagnetism, sediment provenance analysis, and seismology to conclusively constrain Greater Indian paleogeography.

关键词： collision orogenesis subduction reconstruction Himalaya Tibet

The moderating effect of physical activity on the relationship between bullying and mental health among sexual and gender minority youth

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 Sport and Health Science 2023年第1期12卷 106-115页

作者： Sally j.Kirklewski Ryan j.Watson Carolyn Lauckner Department of Health Promotion and Behavior University of GeorgiaAthensGA 30602USA Human Development and Family Sciences University of ConnecticutStorrsCT 06269 USA Department of Behavioral Science University of Kentucky College of MedicineUniversity of KentuckyLexingtonKY 40506USA

Background:Sexual and gender minority youth frequently experience bullying,which often contributes to higher depressive symptoms and lower self-esteem.Given that physical activity(PA)can mitigate depressive symptoms and improve self-esteem,we examined the moderating effect of PA on the relationship between bullying and mental health among sexual and gender minority youth.Methods:Data from the Lesbian,Gay,Bisexual,Transgender,and Queer National Teen Survey(n=9890)were analyzed.Hierarchical regression analyses examined the influence of history and frequency of being bullied,PA,and the interaction of these variables on depressive symptoms and self-esteem.Simple slopes analyses were used to probe significant interactions.Results:Results indicated the importance of accounting for bullying history when examining effects of PA on mental health.PA was negatively related to depression(t=-4.18,p<0.001)and positively related to self-esteem(t=12.11,p<0.001).Bullying frequency was positively related to depression(t=19.35,p<0.001)and negatively related to self-esteem(t=-12.46,p<0.001).There was a significant interaction between bullying frequency and PA for depression(t=4.45,p<0.001)and self-esteem(t=-4.69,p<0.001).Post hoc analyses suggested that the positive effects of PA on mental health may be limited to those not bullied because it had a negligible effect on those who were bullied.Conclusion:Results suggest that sexual and gender minority youth exercise interventions aiming to improve mental health should first address bullying history;otherwise,their effectiveness may be limited to those who have been bullied.

关键词： Bullying Depression Exercise LGBTQ Self-esteem Youth

Natural products and drug discovery

在线全文

学校读者我要写书评

暂无评论

National Science Review 2022年第11期9卷 37-57页

作者： David j.Newman NIH Special Volunteer

This review covers the recent history of a series of very important natural products and their derivatives that are currently in use or under evaluation in the areas of anti-infectives, important cancer treatments that include antibody drug conjugates, followed by a discussion of type 2 diabetes(T2DM) drugs and angiotensin converting enzyme inhibitors. The current structures of the agents are shown, though in the case of some peptides used in T2DM drugs the standard single leTher abbreviation for an amino acid is used.

关键词： artemisinin glycopeptides anthracyclines dolastatin diabetes 2 ACE inhibitors

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

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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

Effect of surface layer softening from previous electrochemical corrosion on electrochemical cold drawing of Q235 steel bar

在线全文

学校读者我要写书评

暂无评论

journal of Iron and Steel Research(International) 2022年第5期29卷 819-835页

作者： j.L.Guo T.j.Chen State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of TechnologyLanzhou730050GansuChina

The effects of H_(2)SO_(4)concentration and current in electrochemical corrosion on surface layer softening or plasticizing of Q235 steel bar and their effects on subsequent electrochemical cold drawing(ECD)were investigated.The results indicate that the electrochemical corrosion can soften or plasticize the surface layer of Q235 steel bar and then make the subsequent ECD be conducted more easily.The softening degree and thickness of the surface layer are continuously enhanced with increasing corrosion rate,i.e.,increasing H_(2)SO_(4)concentration or current,due to the generation of more vacancy clusters in deeper regions of surface layer.These vacancy clusters then relax dislocations through being absorbed during ECD,and the formation and movement of additional dislocation flux are thereby enhanced,resulting in the further obvious decrease in the drawing force.It is also due to the enhanced formation and movement of additional dislocation flux that the dislocation density and thus the hardness of the surface layer are decreased,as well as that the texture structure is weakened.These behaviors are enhanced as the corrosion rate increases.

关键词： Electrochemical corrosion Electrochemical cold drawing Surface layer softening Vacancy Additional dislocation flux