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Comparison of microstructure and mechanical behavior of Ti-35Nb manufactured by laser powder bed fusion from elemental powder mixture and prealloyed powder

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journal of Materials Science & Technology 2022年第10期105卷 1-16页

作者： j.C.Wang Y.j.Liu S.X.Liang Y.S.Zhang L.Q.Wang T.B.Sercombe L.C.Zhang School of Engineering Edith Cowan University270 Joondalup DriveJoondalupPerthWA 6027Australia School of Engineering M050The University of Western Australia35 Stirling HighwayCrawleyPerthWA 6009Australia Northwest Institute for Nonferrous Metal Research Xi’an 710016China State Key Laboratory of Metal Matrix Composites School of Material Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Although different types of powder feedstock are used for additive manufacturing via laser powder bed fusion(L-PBF),limited work has attempted to directly compare the microstructure and mechanical behavior of components manufactured from those powder *** work investigated the microstructure,phase composition,melt pool morphology,and mechanical properties of a prealloyed Ti-35Nb alloy manufactured using L-PBF and compared these to their counterparts produced from elemental powder *** samples manufactured from the powder mixture are composed of randomly distributed undissolved Nb in theα/βmatrix,resulting from the unstable melt pool during the melting of the powder *** contrast,parts produced from prealloyed powder display a homogeneous microstructure withβandαphases,owing to the full melting of prealloyed powder,therefore,a more stable melt pool to achieve a homogeneous *** Ti-35Nb manufactured from prealloyed powder exhibits large tensile ductility(about 10 times that of the counterparts using mixed powder),attributed to the high homogeneity in microstructure and chemical composition,strong interface bonding,relatively low oxygen content,and the existence of a large amount ofβ*** work sheds insights into understanding the effect of powder feedstock on the melt pool stability therefore the microstructure and mechanical behavior of the resultant parts.

关键词： Titanium-niobium Powder bed fusion Additive manufacturing Melt pool stability Microstructure Mechanical properties

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伊萨卡康乃尔大学表演艺术中心,美国

世界建筑 1990年第Z1期 97-99页

作者： j·stirling,M·Wilford&Associates 斯特林、威尔福特事务所

表演艺术中心既是大学的,也是大学所在社区的演出中心。它位于干道边上,靠近横跨峡谷的桥。它的出现,加强了大学与社区之间的联系。它有两个主要立面,一个面临峡谷,一个面临干道。角落处是一个八角亭,把两个立面分开,并且成为市镇的尽... 详细信息

表演艺术中心既是大学的,也是大学所在社区的演出中心。它位于干道边上,靠近横跨峡谷的桥。它的出现,加强了大学与社区之间的联系。它有两个主要立面,一个面临峡谷,一个面临干道。角落处是一个八角亭,把两个立面分开,并且成为市镇的尽端的标志。开幕那一天,建筑师们听到街上有人窃窃私语:“噢,我看它是从佛罗伦萨学来的。”建筑师把外行

关键词：艺术康乃尔大学萨卡

Numerical Simulations of the Performance of Steel Guardrails Under Vehicle Impact

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Transactions of Tianjin University 2008年第5期14卷 318-323页

作者： HAO Hong DEEKS j Andrew WU Chengqing School of Civil and Resource Engineering the University of Western Australia 35 Stirling Highway Crawley WA 6009 Australia School of Civil Environmental and Mining Engineering the University of Adelaide North Terrace SA5005 Australia

Road side barriers are constructed to protect passengers and contain vehicles when a vehicle crashes into a barrier. In general, full-scale crash testing needs to be carried out if a geometrically and structurally equivalent barrier has not previously been proven to meet the requirements of containing the vehicle and dissipating sufficient impact energy for passenger protection. As full-scale crash testing is very expensive, the number of data that can be measured in a test is usually limited, and it may not always be possible to obtain good quality measurements in such a test, a reliable and efficient numerical simulation of crash testing is therefore very useful. This paper presents finite element simulations of a 3-rail steel road traffic barrier under vehicle impact. The performance levels defined in Australian Standards AS5100 Clause 10.5 for these barriers are checked. The numerical simulations show that the barrier is able to meet low performance levels. However, the maximum deceleration is higher than the acceptable limit for passenger protection. If present, a kerb launches the vehicles into the barrier, allowing for the possibility of overriding the barrier under certain circumstances, but it redirects the vehicle and reduces the incident angle, which reduces impact force on the barrier. Further investigation into all common kerb profiles on roads should be carried out, as only one kerb profile is investigated in this study.

关键词：车辆碰撞钢护栏边石交通堵塞乘客保护

Incorporating novelty and novel ecosystems into restoration planning and practice in the 21st century

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Ecological Processes 2013年第1期2卷 175-182页

作者： Michael P Perring Rachel j Standish Richard j Hobbs Ecosystem Restoration and Intervention Ecology Research Group School of Plant BiologyThe University of Western Australia35 Stirling HighwayCrawleyWA 6009Australia

Novelty pervades the *** some cases,potentially irreversible abiotic and/or biotic changes have led to the crossing of thresholds and thus the formation of“novel ecosystems.”Their widespread emergence(particularly on land)and the presence of continued environmental change challenge a traditional restoration goal of restoring an historical ***,we argue that restoration could broaden its frame of reference to consider how novel ecosystems might be used to maintain global biodiversity and provide ecosystem services and,in doing so,save potentially wasted efforts in attempting to fulfil traditional *** we explore this contention in more depth by addressing:Are novel ecosystems innovative planning or lowering the bar?We show that novel ecosystems were not innovative planning in their original *** the contrary,they were recognized as ecosystems that were recalcitrant to traditional restoration approaches,coupled with an awareness that they had arisen inadvertently through deliberate human activity,either on-or *** recalcitrance to traditional restoration suggests that alternative goals may exist for these ecosystems using sometimes innovative *** management may include biodiversity conservation or restoration for ecological *** elucidate the latter aspect with reference to an experiment in the wheatbelt of Western Australia—The Ridgefield Multiple Ecosystem Services Experiment—the design of which has been informed by ecological theory and the acceptance of novelty as an ecosystem *** novel ecosystems do provide opportunities to broaden restoration planning and practice,and ultimately maintain and conserve global biodiversity in this era of environmental change,they necessarily“lower the bar”in restoration if the bar is considered to be the historical ***,in these times of flux,such a bar is increasingly ***,careful and appropriate interventions are required

关键词： No-analogue ecosystem Biodiversity conservation Ecosystem function Ecological restoration Restoration baseline Ridgefield multiple ecosystem services experiment York gum woodland

A review on MBE-grown HgCdSe infrared materials on GaSb(211)B substrates

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Chinese Physics B 2019年第1期28卷 116-125页

作者： Z K Zhang W W Pan j L Liu W Lei Department of Electrical Electronic and Computer EngineeringThe University of Western Australia35 Stirling HighwayCrawley 6009Australia

We review our recent efforts on developing HgCdSe infrared materials on Ga Sb substrates via molecular beam epitaxy(MBE) for fabricating next generation infrared detectors with features of lower production cost and larger focal plane array format size. In order to achieve high-quality HgCdSe epilayers, ZnTe buffer layers are grown before growing HgCdSe, and the study of misfit strain in ZnTe buffer layers shows that the thickness of ZnTe buffer layer needs to be below 300 nm in order to minimize the generation of misfit dislocations. The cut-off wavelength/alloy composition of HgCdSe materials can be varied in a wide range by varying the ratio of Se/Cd beam equivalent pressure during the HgCdSe *** temperature presents significant impact on the material quality of HgCdSe, and lower growth temperature leads to higher material quality for HgCdSe. Typically, long-wave infrared HgCdSe(x = 0.18, cut-off wavelength of 10.4 μm at 80 K) presents an electron mobility as high as 1.3×10~5cm^2·V^(-1)·s^(-1), a background electron concentration as low as 1.6×10^(16)cm^(-3), and a minority carrier lifetime as long as 2.2 μs. These values of electron mobility and minority carrier lifetime represent a significant improvement on previous studies of MBE-grown HgCdSe reported in the open literatures,and are comparable to those of counterpart HgCdTe materials grown on lattice-matched CdZnTe substrates. These results indicate that HgCdSe grown at the University of Western Australia, especially long-wave infrared can meet the basic material quality requirements for making high performance infrared detectors although further effort is required to control the background electron concentration to below 10^(15)cm^(-3). More importantly, even higher quality HgCdSe materials on GaSb are expected by further optimizing the growth conditions, using higher purity Se source material, and implementing postgrowth thermal annealing and defect/impurity gettering/filtering. Our results demonst

关键词： infrared detector HgCdSe GaSb molecular beam epitaxy

Application Prospect of Fission-Powered Spacecraft in Solar System Exploration Missions

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Space(Science & Technology) 2021年第1期2021卷 309-323页

作者： Y.Xia j.Li R.Zhai j.Wang B.Lin Q.Zhou Beijing Institute of Spacecraft Environment Engineering BeijingChina Science and Technology on Reliability and Environmental Engineering Laboratory BeijingChina Institute of Nuclear and New Energy Technology of Tsinghua University The Key Laboratory of Advanced Reactor Engineering and SafetyMinistry of EducationBeijingChina

Fission power is a promising technology,and it has been proposed for several future space *** is being considered for highpower missions whose goal is to explore the solar system and even *** fission power has made great progress when NASA’s 1 kWe Kilowatt Reactor Using stirling TechnologY(KRUSTY)prototype completed a full power scale nuclear test in *** success stimulated a new round of research competition among the major space *** article reviews the development of the Kilopower reactor and the KRUSTY system *** summarizes the current missions that fission reactors are being considered as a power and/or propulsion *** projects include visiting jupiter and Saturn systems,Chiron,and Kuiper belt object;Neptune exploration missions;and lunar and Mars surface base *** studies suggest that the Fission Electric Propulsion(FEP)/Fission Power System(FPS)is better than the Radioisotope Electric Propulsion(REP)/Radioisotope Power System(RPS)in the aspect of cost for missions with a power level that reaches~1 kWe,and when the power levels reaches~8 kWe,it has the advantage of lower *** a mission that travels further than~Saturn,REP with plutonium may not be cost acceptable,leaving FEP the only *** missions prefer the use of FPS because it satisfies the power level of 10’s kWe,and FPS vastly widens the choice of possible landing *** to the current situation,we are expecting a flagship-level fission-powered space exploration mission in the next 1-2 decades.

关键词： satis Saturn isotope

原发性乳腺癌:化疗前和化疗期间固有磁敏感加权成像与组织学相关性研究

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国际医学放射学杂志 2011年第1期34卷 79-80页

作者： N.j.Taylor A.Makris M.L.Ah-See M.j.Beresford j.j.stirling 路红 Academic Oncology Unit Mount Vernon Cancer Centre

目的探讨原发性乳腺癌固有磁敏感加权(ISW)成像与MR动态成像和组织学表现的相关性,并评价化疗前基线横向弛豫率(R2*)、T2*弛豫变化(ΔR2*)与新辅助化疗(NAC)

关键词：乳腺癌磁敏感基线相关性乳腺肿瘤原发性

Identification of factors predicting scar outcome after burn injury in children:a prospective case-control study

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Burns & Trauma 2017年第3期5卷 186-198页

作者： Hilary j. Wallace Mark W. Fear Margaret M. Crowe Lisa j. Martin Fiona M. Wood Burn Injury Research Unit Faculty of Health and Medical Sciences University of Western Australia Perth WA Australia Burn Injury Research Unit Faculty of Health and Medical Sciences University of Western Australia M318 35 Stirling Highway Crawley 6009 WA Australia Burn Injury Research Unit Faculty of Health and Medical Sciences University of Western Australia Perth WA Australia Burns Service of Western Australia Princess Margaret Hospital for Children and Fiona Stanley Hospital Perth WA Australia Burn Injury Research Unit Faculty of Health and Medical Sciences University of Western Australia Perth WA Australia Burns Service of Western Australia Princess Margaret Hospital for Children and Fiona Stanley Hospital Perth WA Australia

Background:There is a lack of rigorous research investigating the factors that influence scar outcome in children. Improved clinical decision-making to reduce the health burden due to post-burn scarring in children will be guided by evidence on risk factors and risk stratification. This study aimed to examine the association between selected patient, injury and clinical factors and the development of raised scar after burn injury. Novel patient factors were investigated including selected immunological co-morbidities (asthma, eczema and diabetes type 1 and type 2) and skin pigmentation (Fitzpatrick skin type). Methods:A prospective case-control study was conducted among 186 children who sustained a burn injury in Western Australia. Logistic regression was used to explore the relationship between explanatory variables and a defined outcome measure:scar height measured by a modified Vancouver Scar Scale (mVSS). Results:The overall correct prediction rate of the model was 80.6%;80.9%for children with raised scars (>1 mm) and 80.4%for children without raised scars (≤1 mm). After adjustment for other variables, each 1%increase in%total body surface area (%TBSA) of burn increased the odds of raised scar by 15.8%(95%CI=4.4-28.5%). Raised scar was also predicted by time to healing of longer than 14 days (OR=11.621;95%CI=3.727-36.234) and multiple surgical procedures (OR=11.521;1.994-66.566). Conclusions:Greater burn surface area, time to healing of longer than 14 days, and multiple operations are independently associated with raised scar in children after burn injury. Scar prevention strategies should be targeted to children with these risk factors.

关键词： Burns Wound healing Hypertrophic scar Risk factors Children

动态增强MR成像对新辅助化疗原发性乳腺癌生存期的预测

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国际医学放射学杂志 2011年第5期 472-473页

作者： A.Makris M.j.Beresford N.j.Taylor M.L.W.Ah-See j.j.stirling 刘芳 Academic Oncology Unit Mount Vernon Cancer CentreRickmansworth RdNorthwoodMiddlesexHA6 2RNEngland

目的探讨原发性乳腺癌2个周期新辅助化疗(NAC)后行动态增强MR成像并测量其早期血管参数变化以预测无病生存期和总生存期的可行性。材料与方法本研

关键词：乳腺癌总生存期无病生存乳腺肿瘤动态增强新辅助化疗原发性 MR