检索结果-南通市图书馆

Palladium-catalyzed S_(N)2 glycosylation of phenols

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第4期67卷 1037-1038页

作者： Yu Zhu P.andrew Evans Department of Chemistry Queen’s University90 Bader LaneKingstonK7L 3N6Canada Xiangya School of Pharmaceutical Sciences Central South UniversityChangsha 410013China

Glycosides are essential structural motifs present in an array of important medicines,materials,and natural products[1].Nevertheless,the chemo-and stereoselective construction of the glycosidic linkage is a long-standing challenge because relatively minor variations in the glycosyl donor or acceptor’s structure can impact stereoselectivity,thus influencing the product's functional properties.

关键词： properties Palladium catalyzed

On Some Cycles in Wenger Graphs

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2020年第2期36卷 492-502页

作者： Ye WANG Felix LAZEBNIK andrew THOMASON College of Mathematical Sciences Harbin Engineering UniversityHarbin 150001China Department of Mathematical Sciences University of DelawareNewark.DE 19716U.S.A. DPMMS Centre for Mathematical SciencesWilberforce RoadCambridgeUK

Let p be a prime,q be a power of p,and let Fq be the field of q *** any positive integer n,the Wenger graph Wn(q)is defined as follows:it is a bipartite graph with the vertex partitions being two copies of the(n+1)-dimensional vector space Fq^n+1,and two vertices p=(p(1),…,p(n+1))and l=[l(1),…,l(n+1)]being adjacent if p(i)+l(i)=p(1)l(1)i-1,for all i=2,3,…,n+*** 2008,Shao,He and Shan showed that for n≥2,Wn(q)contains a cycle of length 2 k where 4≤k≤2 p and k≠*** this paper we extend their results by showing that(i)for n≥2 and p≥3,Wn(q)contains cycles of length 2k,where 4≤k≤4 p+1 and k≠5;(ii)for q≥5,0

关键词： cycle pancyclic finite field Wenger graph graph embeddings

Teleseismic waves reveal anisotropic poroelastic response of wastewater disposal reservoir

在线全文

学校读者我要写书评

暂无评论

Earth and Planetary Physics 2021年第6期5卷 547-558页

作者： andrew J Barbour Nicholas M Beeler u.s.geological survey earthquake science centerusa

Connecting earthquake nucleation in basement rock to fluid injection in basal,sedimentary reservoirs,depends heavily on choices related to the poroelastic properties of the fluid-rock system,thermo-chemical effects *** constraints on these parameters outside of laboratory settings are rare,and it is commonly assumed that the rock layers are *** the Arbuckle wastewater disposal reservoir in Osage County,Oklahoma,high-frequency formation pressure changes and collocated broadband ground velocities measured during the passing of large teleseismic waves show a poroelastic response of the reservoir that is both azimuthally variable and anisotropic;this includes evidence of static shifts in pressure that presumably relate to changes in local *** azimuthal dependence in both the static response and shear coupling appears related to tectonic stress and strain indicators such as the orientations of the maximum horizontal stress and faults and *** dynamic strains from a nearby borehole strainmeter,we show that the ratio of shear to volumetric strain coupling is~0.41 which implies a mean Skempton's coefficient of A=0.24 over the plausible range of the undrained Poisson's *** these observations are made at relatively low confining pressure and differential stress,we suggest that the hydraulically conductive fracture network is a primary control on the coupling between pore pressure diffusion and elastic stresses in response to natural or anthropogenic sources.

关键词： poroelasticity dynamic strain anisotropy wastewater disposal Oklahoma induced seismicity

Atomistic learning in the electronically grand-canonical ensemble

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 1619-1627页

作者： Xi Chen Muammar El Khatib Per Lindgren Adam Willard andrew J.Medford andrew A.Peterson School of Engineering Brown UniversityProvidenceRI 02912USA Department of Chemistry Massachussetts Institute of TechnologyCambridgeMAUSA School of Chemical and Biomolecular Engineering Georgia Institute of TechnologyAtlantaGA 30318USA

A strategy is presented for the machine-learning emulation of electronic structure calculations carried out in the electronically grand-canonical *** approach relies upon a dual-learning scheme,where both the system charge and the system energy are predicted for each *** scheme is shown to be capable of emulating basic electrochemical reactions at a range of potentials,and coupling it with a bootstrap-ensemble approach gives reasonable estimates of the prediction *** method is also demonstrated to accelerate saddle-point searches,and to extrapolate to systems with one to five water *** anticipate that this method will allow for larger length-and time-scale simulations necessary for electrochemical simulations.

关键词： canonical ensemble electronic

Historical imaginaries, historic urban branding, and the local state in China: rejuvenation discourse, manufactured heritage and simulacrascapes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Built Heritage 2023年第1期7卷 76-87页

作者： andrew Malcolm Law School of Architecture Planning and LandscapeNewcastle UniversityNewcastleUK

This intervention examines the extant literature on historical imaginaries and historic urban branding in *** suggests that while research in this field has increasingly moved away from an economic(or an implicit neo-Marxist)model,there is still a lack of research on the role of broader cultural and state led discourses of nationalism in the construction of historic urban imaginaries and historic urban branding within Chinese *** unpacking one nationalistic discourse a-narrative of rejuvenation-this article argues that more needs to be done to examine the role of these themes in the construction of historical imaginaries at the level of the local state(including related state networks of developers,retailers,tourist officials,town planners,architects,and designers).It is suggested that an analysis of these discourses and imaginaries is important if we are:1)to appreciate the role of these themes in the construction and/or the reconfiguration of existing or emerging historic brands within Chinese cities;2)to comprehend the construction of'authorised heritage discourses,(AHDs)practices and materialities at the level of the local state;3)to understand the politics of the past(including the uses of history,memory,nostalgia,and heritage)at the level of the local state;4)to be aware of the way in which these themes inform the preservation,conservation,and/or the demolition of heritage space at the level of the local state;5)to recognise the manufacture of'heritage'or simulacrascapes within Chinese cities.

关键词： rejuvenation historical urban imaginaries historical urban branding built heritage simulacrascapes

Do black-furred animals compensate for high solar absorption with smaller hairs？ A test with a polymorphic squirrel species

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2011年第6期57卷 731-736页

作者： Melanie A. FRATTO andrew K. DAVIS Odum School of Ecology The University of Georgia Athens GA USA 30602

In polymorphic mammalian species that display multiple color forms, those with dark, or melanic pelage would be prone to overheating, especially if they live in warm climates, because their fur absorbs solar energy at a higher rate. However, experimental studies indicate that certain physical properties of fur of dark individuals appear to prevent, or minimize heat stress, although it is not clear what properties do so. Here, we tested the possibility that black-furred individuals simply have shorter or thinner hair fibers, which would create a lighter （in terms of weight） coat or one that allows greater air flow for evaporative coo- ling. We examined museum specimens of eastern fox squirrels Sciurus niger, a species native to the United States and one that displays brown, grey or all-black pelage color, and used image analysis procedures to quantify hairs from the dorsal surface and tail. From examination of 43 specimens （19 brown, 9 black and 15 grey）, and 1,720 hairs, we found no significant difference in hair lengths across color morphs, but significant differences in hair fiber widths. Black squirrels had thinner body hairs than other forms （7% thinner）, but thicker tail hairs （9% thicker） than the others. Given that the dorsal surface would be directly exposed to solar radiation, we interpret this to be an adaptation to prevent heat stress during the day. The thicker tail hairs may be an adapta- tion for nighttime thermoregulation, since squirrels sleep with their tails wrapped around their bodies. These results add to a growing literature body of the functional significance of mammalian pelage [Current Zoology 57 （6）： 731-736, 2011].

关键词： Polymorphism Melanism Fox squirrels Sciurus niger Heat stress Hair morphology

Sexual dimorphism in cranial shape and size in geomyoid rodents:multivariate and evolutionary perspectives

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2022年第4期68卷 469-487页

作者： Jonathan J M Calede andrew Brown Department of Evolution Ecologyand Organismal BiologyThe Ohio State University318 W.12th Ave.300 Aronoff LaboratoryColumbusOH 43210USA The Ohio State University at Marion 1459 Mount Vernon AvenueMarionOH 43302USA College of Veterinary Medicine Texas A&M University660 Raymond Stotzer PkwyCollege StationTX 77843USA

Geomyoid rodents provide a great study system for the analysis of sexual *** are polygynic and many inhabit harsh arid environments thought to promote sexual *** fact,there has been extensive work published on the sexual size dimorphism of individual populations and species within this rodent ***,little work has been undertaken to assess the evolutionary patterns and processes associated with this sexual *** use multivariate analyses of cranial measurements in a phylogenetic framework to determine the distribution of size and shape dimorphism among geomyoids and test for Rensch’s *** results suggest that sexual dimorphism is more common in geomyids than heteromyids,but it is not in fact *** is evidence for variation in sexual dimorphism across ***,in many taxa,geographic variation appears to overwhelm existing sexual *** find support for the repeated independent evolution of shape and size dimorphism across geomyoid taxa,but we do not find support for an association between size and shape *** is no evidence for Rensch’s rule in geomyoids,whether at the superfamily or family ***,our findings suggest that there is no single explanation for the evolution of sexual dimorphism in geomyoids and that,instead,it is the product of numerous evolutionary *** studies incorporating phylogenetic relationships will be necessary to paint a more complete picture of the evolution of sexual dimorphism in geomyoids.

关键词： Geomyidae Heteromyidae phylogenetic comparative methods morphometrics Rensch’s rule

On Desideratum for B2C E-Commerce Reputation Systems

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 Computer Science & Technology 2009年第5期24卷 820-832页

作者： Anna Gutowska andrew Sloane Kevan A.Buckley School of Computing and Information Technology University of WolverhamptonWolverhamptonWV1 1SBU.K.

This paper reviews existing approaches to reputation systems, their constraints as well as available solutions. Furthermore, it presents and evaluates a novel and comprehensive reputation model devoted to the distributed reputation system for Business-to-Consumer （B2C） E-commerce applications that overcomes the discussed drawbacks. The algorithm offers a comprehensive approach as it considers a number of issues that have a bearing on trust and reputation such as age of ratings, transaction value, credibility of referees, number of malicious incidents, collusion and unfair ratings. Moreover, it also extends the existing frameworks based on information about past behaviour, with other aspects affecting online trading decisions which relate to the characteristic of the providers, such as existence of trustmark seals, payment intermediaries, privacy statements, security/privacy strategies, purchase protection/insurance, alternative dispute resolutions as well as the existence of first party information.

关键词： decision support distributed systems electronic commerce online information services

STORMWATER NATURE POCKETS: A CASE FOR USING GREEN INFRASTRUCTURE TO CREATE ENGAGING CHILDHOOD SPACES

在线全文

学校读者我要写书评

暂无评论

Journal of Green Building 2015年第3期10卷 14-27页

作者： Adrienne Cizek andrew Fox Stormwater Solutions Engineering LLC North Carolina State University Department of Landscape Architecture

Urban areas require stormwater *** there has been a movement towards more nature-based,green infrastructure approaches for managing *** systems have also demonstrated additional ecosystem benefits much needed in urban *** the same time,decades of research support the need for access to nature for healthy childhood *** and locating nature-based stormwater systems where children frequent renders systems as multi-functional spaces,providing synergetic opportunities,which benefit individuals and *** to integrating these spaces include safety,cost,and management,all of which can be overcome by smart and appropriate *** design requires collaboration between different skillsets and stakeholders through some minimal,but essential changes in the consultation and design ***,integrating nature-based stormwater practices into children’s outdoor spaces will provide economic,environmental,and social benefits to urban areas.

关键词： green infrastructure low impact development outdoor learning environments nature play stormwatersoil biology plant factor evapotranspiration drip irrigation organic maintenance hands-on workshop