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Large open-circuit voltage polymer solar cells by poly(3-hexylthiophene) with multi-adducts fullerenes

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Science China Chemistry 2012年第5期55卷 743-748页

作者： HEEGER alan j. Department of Physics University of California Santa Barbara USA

Polymer solar cells (PSCs) made by poly(3-hexylthiophene) (P3HT) with multi-adducts fullerenes, [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM), PC61BM-bisadduct (bisPC61BM) and PC61BM-trisadduct (trisPC61BM), were reported. Electrochemistry studies indicated that PC61BM, bisPC61BM and trisPC61BM had step-up distributional lowest unoccupied molecular orbital (LUMO) energy. PSCs made by P3HT with above PC61BMs show a trend of enlarged open-circuit voltages, which is in good agreement with the energy difference between the LUMO of PC61BMs and the HOMO of P3HT. On the contrary, reduced short-circuit currents (j.c) were observed. The investigation of photo responsibility, dynamics analysis based on photo-induced absorption of composite films, P3HT:PC61BMs and n-channel thin film field-effect transistors of PC61BMs suggested that the short polaron lifetimes and low carrier mobilities were response for reduced j.c. All these results demonstrated that it was important to develop an electron acceptor which has both high carrier mobility, and good compatibility with the electron donor conj.gated polymer for approaching high performance PSCs.

关键词： fullerene derivative large open circuit voltage polaron lifetime charge carrier mobility

ecent advances in selective acetylene hydrogenation using palladium containing catalysts

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Frontiers of Chemical Science and Engineering 2015年第2期9卷 142-153页

作者： alan j. McCue j.mes A. Anderson Surface Chemistry and Catalysis Group Department of Chemistry University of Aberdeen Aberdeen AB24 3UE UK Materials and Chemical Engineering Group School of Engineering University of Aberdeen Aberdeen AB24 3UE UK

Recent advances with Pd containing catalysts for the selective hydrogenation of acetylene are described. The overview classifies enhancement of catalytic proper- ties for monometallic and bimetallic Pd catalysts. Activity/ selectivity of Pd catalysts can be modified by controllingparticle shape/morphology or immobilisation on a support which interacts strongly with Pd particles. In both cases enhanced ethylene selectivity is generally associated with modifying ethylene adsorption strength and/or changes to hydride formation. Inorganic and organic selectivity modifiers （i.e., species adsorbed onto Pd particle surface） have also been shown to enhance ethylene selectivity. Inorganic modifiers such as TiO2 change Pd ensemble size and modify ethylene adsorption strength whereas organic modifiers such as diphenylsulfide are thought to create a surface template effect which favours acetylene adsorption with respect to ethylene. A number of metals and synthetic approaches have been explored to prepare Pd bimetallic catalysts. Examples where enhanced selectivity is observed are generally associated with decreased Pd ensemble size and/or hindering of the ease with which an unselective hydride phase is formed for Pd. A final class of bimetallic catalysts are discussed where Pd is not thought to be the primary reaction site but merely acts as a site where hydrogen dissociation and spillover occurs onto a second metal （Cu or Au） where the reaction takes place more selectively.

关键词： acetylene ethylene selective hydrogenation,palladium bimetallic

Sexual selection affects the sizes of the mammalian prostate gland and seminal vesicles

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Current Zoology 2009年第1期55卷 1-8页

作者： Matthew j. ANDERSON alan F. DIXSON Conservation and Research for Endangered Species Zoological Society of San Diego School of Biological Sciences Victoria University of Wellington

The accessory reproductive glands of male mammals contribute the bulk of the secretions in which spermatozoa are transported to the female tract during copulation. Despite their morphological diversity, and the chemical complexity of their products, little is known about the possible effects of sexual selection upon these glands in mammals. Here we consider the seminal vesicles and prostate glands in a sample of 89 species and 60 genera representing 8 Orders of mammals. The sizes of the accessory glands are analysed in relation to body weight and testes weight. Both the seminal vesicles size and prostate size （corrected for body weight） correlate positively with relative testes size in this sample; this finding remains highly significant after application of procedures to correct for possible phylogenetic biases in the data set. The accessory reproductive glands are also significantly larger in those mammals which have large relative testes sizes, and in which the likelihood of sperm competition is greatest. These results support the hypothesis that sexual selection has played an important role in the evolution of the mammalian prostate gland and seminal vesicles.

关键词： Mammals Prostrate gland Seminal vesicles Sexual selection Sperm competition

Engineering heterogenous catalysts for chemical CO_(2) utilization:Lessons from thermal catalysis and advantages of yolk@shell structured nanoreactors

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j.urnal of Energy Chemistry 2021年第6期30卷 304-324,I0008页

作者： Cameron Alexander hurd Price Tomas Ramirez Reina j.an Liu DICP-Surrey j.int Centre for Future Materials Department of Chemical and Process EngineeringUniversity of SurreyGuildfordSurrey GU27XHUK State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

The development of catalytic materials for the recycling CO_(2) through a myriad of available processes is an attractive field,especially given the current climate *** there is increasing publication in this field,the reported catalysts rarely deviate from the traditionally supported metal nanoparticle morphology,with the most simplistic method of enhancement being the addition of more metals to an already complex *** catalysts,especially yolk@shell catalysts with hollow voids,offer answers to the most prominent issues faced by this field,coking and sintering,and further potential for more advanced phenomena,for example,the confinement effect,to promote selectivity or offer greater protection against coking and *** work serves to demonstrate the current position of catalyst development in the fields of thermal CO_(2) reforming and hydrogenation,summarizing the most recent work available and most common metals used for these reactions,and how yolk@shell catalysts can offer superior performance and survivability in thermal CO_(2) reforming and hydrogenation to the more traditional ***,this work will briefly demonstrate the bespoke nature and highly variable yolk@shell ***,this review aims to illuminate the spatial confinement effect and how it enhances yolk@shell structured nanoreactors is presented.

关键词： Yolk@shell CO_(2)utilization Reforming Hydrogenation Confinement effect

Massive energy storage systems enable secure electricity supply from renewables

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j.urnal of Modern Power Systems and Clean Energy 2016年第4期4卷 659-667页

作者： alan j.SANGSTER School of Engineering and Physical Sciences Heriot-Watt UniversityRiccarton CampusEdinburgh EH144ASUK

Climate change is mainly attributed to the burning of fossil *** solve the problem,current inhabitants have to dispense with fossil fuels as a source of *** has been demonstrated that this can be secured before 2050 by transitioning to renewable sources of *** energy storage(MES)incorporated into long distance high voltage direct current(HVDC)transmission systems is the key technology for the *** paper describes the current state-of-the-art in electricity grid *** demonstrates how MES,and other back-up local electricity storage schemes represent a natural way of buffering electricity consumers from the intermittency of inherent in the primary renewable ***,it can solve the base-load issues and facilitate a global transition to 100%renewable energy sources over the next fifteen to twenty years.

关键词： Electricity grid Energy storage Pumpedhydro Lagoon storage Hydraulic piston Climate change

Gold modified cobalt-based Fischer-Tropsch catalysts for conversion of synthesis gas to liquid fuels

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Frontiers of Chemical Science and Engineering 2013年第3期7卷 262-269页

作者： alan j. Mccue j.ra Aponaviciute Richard P.K. Wells j.mes A. Anderson Surface Chemistry and Catalysis Group Department of Chemistry University of Aberdeen AB24 3UE Abcrdccn UK Surface Chemistry and Catalysis Group School of Engineering University of Aberdeen AB24 3UE Aberdeen UK

The addition of Au as a promoter/modifier for alumina supported Co catalyst has been studied by combined in-situ high temperature, high pressure Fourier transform infrared （FTIR） and on-line gas chromatography. The combination of these tools permitted the state of the active catalyst surface to be monitored while following the elution of reaction products during the first 5-7 h on stream of the catalyst. The catalysts under study were a 10%Co/ A1203 and a 2.5%Au/10%Co/A1203. Samples were characterised before use using Raman and temperature programmed reduction （TPR）. During the initial stages of reaction, hydrocarbons were built up on the surface of the catalyst as monitored by FTIR and the nature and amount of these species were assessed in terms of CH2/CH3 ratio and the density of these alkyl fragments by employing absorption coefficients for the individual components. The nature and reducibility of the Co particles were modified by the presence of Au while the later also shifted the CO/ H2 balance by acting as an effective water-gas shift catalyst during the early stages of reaction. This characteristic was lost during reaction as a consequence of redistribution of the two metallic phases.

关键词： gold modified catalyst conversion of synthesis gas

COVID-19: Analytics of contagion on inhomogeneous random social networks

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Infectious Disease Modelling 2021年第1期6卷 75-90页

作者： T.R.hurd Mathematics&Statistics McMaster University1280 Main St.WestHamiltonOntarioL8S 4L8Canada

Motivated by the need for robust models of the Covid-19 epidemic that adequately reflect the extreme heterogeneity of humans and society,this paper presents a novel framework that treats a population of N individuals as an inhomogeneous random social network(IRSN).The nodes of the network represent individuals of different types and the edges represent significant social *** epidemic is pictured as a contagion process that develops day by day,triggered by a seed infection introduced into the population on day ***’social behaviour and health status are assumed to vary randomly within each type,with probability distributions that vary with their type.A formulation and analysis is given for a SEIR(susceptible-exposed-infective-removed)network contagion model,considered as an agent based model,which focusses on the number of people of each type in each compartment each *** main result is an analytical formula valid in the large N limit for the stochastic state of the system on day t in terms of the initial *** formula involves only one-dimensional *** model can be implemented numerically for any number of types by a deterministic algorithm that efficiently incorporates the discrete Fourier *** the paper focusses on fundamental properties rather than far ranging applications,a concluding discussion addresses a number of domains,notably public awareness,infectious disease research and public health policy,where the IRSN framework may provide unique insights.

关键词： Social network Infectious disease model Complex systems Agent based model Cascade model Poisson random graphs

Modeling the dose-response rate/associations between VO2max and self-reported Physical Activity Questionnaire in children and adolescents

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j.urnal of Sport and Health Science 2020年第1期9卷 90-95页

作者： alan M.Nevill Michael j.Duncan Gavin Sandercock Faculty of Education Health and WellbeingUniversity of WolverhamptonWalsall CampusWalsallWS13BDUK Faculty of Health and Life Sciences Coventry UniversityCoventryCV15FBUK School of Biological Sciences University of EssexColchesterCO43SQUK

Background'. This study sought to explore the dose—response rate/association between aerobic fitness (VC)2max) and self-reported physical activity(PA) and to assess whether this association varies by sex, age, and weight ***. VO2max was assessed using the 20・m shuttle・run test. PA was assessed using the Physical Activity Questionnaire (PAQ) for Adolescents(aged > 11 years, PAQ-A) or for Children (aged <11 years, PAQ-C). The associations between V02raax and PAQ were analyzed using analysisof covariance (ANCOVA), adopting PAQ and PAQ2 as covariates but allowing the intercepts and slope parameters of PAQ and PAQ2 tovary with the categorical variables sex, age group, and weight ***: ANCOVA identified a curvilinear association between VO2max and PAQ, with positive linear PAQ terms that varied for both sex andweight status but with a negative PAQ2 term of —0.39 (95% confidence interval (CI): —0.57 to —0.21) that was common for all groups in regardto age, sex, and weight status. These curvilinear (inverted U) associations suggest that the benefits of increasing PA (same dose) on VO2max isgreater when children report lower levels of PA compared to children who report higher levels of PA. These dose-response rates were alsosteeper for boys and were steeper for lean children compared to overweight/obese ***'. Health practitioners should be aware that encouraging greater PA (same dose) in inactive and underweight children will result ingreater gains in V02max (response) compared with their active and overweight/obese counterparts.

关键词： Aerobic fitness Curvilinear association Sex Slope parameters Weight status

A novel method for determination of lethal radius for high-explosive artillery proj.ctiles

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Defence Technology（防务技术） 2021年第4期17卷 1217-1233页

作者： alan Catovic Elvedin Klj.no Mechanical Engineering Faculty(Defense Technology Department) University of SarajevoSarajevoBosnia and Herzegovina Mechanical Engineering Faculty University of SarajevoSarajevoBosnia and Herzegovina

A new model has been defined that enables the estimation of the lethal radius(radius of efficiency)of HE(High Explosive)artillery proj.ctiles against human *** model is made of several modules:CAD(Computer Aided Design)modeling,fragment mass distribution estimation,fragment initial velocity prediction,fragment traj.ctory calculation,effective fragment density estimation,and high explosive proj.ctile lethal radius *** results were compared with the experimental results obtained based on tests in the arena used in our country,and the agreement of the results was *** model can be used in any terminal-ballistics scenario for high explosive proj.ctiles since it is general,parametric,fast and relatively easy to implement.

关键词： High explosive proj.ctiles Lethal radius Fragments Modeling