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npj Computational Materials 2023年第1期9卷 1866-1879页

作者： danial Khatamsaz Brent Vela Prashant Singh duane d.Johnson douglas Allaire Raymundo Arróyave J.Mike Walker’66 department of Mechanical Engineering Texas A&M UniversityCollege StationTX 77843USA department of Materials Science and Engineering Texas A&M UniversityCollege StationTX 77843USA Ames Laboratory U.S.Department of EnergyIowa State UniversityAmesIA 50011USA department of Materials Science&Engineering Iowa State UniversityAmesIA 50011USA department of Industrial and Systems Engineering Texas A&M UniversityCollege StationTX 77843USA

The design of alloys for use in gas turbine engine blades is a complex task that involves balancing multiple objectives and *** alloys must be ductile at room temperature and retain their yield strength at high temperatures,as well as possess low density,high thermal conductivity,narrow solidification range,high solidus temperature,and a small linear thermal expansion *** Integrated Computational Materials Engineering(ICME)methods are not sufficient for exploring combinatorially-vast alloy design spaces,optimizing for multiple objectives,nor ensuring that multiple constraints are *** this work,we propose an approach for solving a constrained multi-objective materials design problem over a large composition space,specifically focusing on the Mo-Nb-Ti-V-W system as a representative Multi-Principal Element Alloy(MPEA)for potential use in next-generation gas turbine *** approach is able to learn and adapt to unknown constraints in the design space,making decisions about the best course of action at each stage of the *** a result,we identify 21 Pareto-optimal alloys that satisfy all *** proposed framework is significantly more efficient and faster than a brute force approach.

关键词： alloys solidification alloy

design of refractory multi-principal-element alloys for high-temperature applications

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npj Computational Materials 2023年第1期9卷 884-893页

作者： Gaoyuan Ouyang Prashant Singh Ranran Su duane d.Johnson Matthew J.Kramer John H.Perepezko Oleg N.Senkov daniel Miracle Jun Cui division of Materials Science and Engineering Ames LaboratoryAmesIA 50011USA department of Materials Science and Engineering University of Wisconsin-MadisonMadisonWI 53706USA department of Materials Science and Engineering Iowa State UniversityAmesIA 50011USA Air Force Research Laboratory Materials and Manufacturing DirectorateWright-Patterson Air Force BaseDaytonOH 45433USA

Refractory multi-principal-element alloys(RMPEAs)exhibit high specific strength at elevated temperatures(T).However,current RMPEAs lack a balance of room-temperature(RT)ductility,high-T strength,and high-T creep *** density-functional theory methods,we scanned composition space using four criteria:(1)formation energies for operational stability:-150d via interstitial electron density with Young’s moduli E>250 GPa;(3)inverse Pugh ratio for ductility:G/Bd(4)high melting points:T_(m)>2500°*** rapid bulk alloy synthesis and characterization,we validated theory and down-selected promising alloy compositions and discovered Mo72.3W12.8Ta10.0Ti2.5Zr2.5 having well-balanced RT and high-T mechanical *** alloy has comparable high-T compressive strength to well-known MoNbTaW but is more ductile and more creep *** is also superior to a commercial Mo-based refractory alloy and a nickel-based superalloy(Haynes-282)with improved high-T tensile strength and creep resistance.

关键词： creep alloy alloys

Anion structural effects on interaction of rare earth element ions with dowex 50W X8 cation exchange resin

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Journal of Rare Earths 2018年第8期36卷 879-890页

作者： duane d.Miller Ranjani Siriwardane dustin Mcintyre U.S. department of Energy National Energy Technology Laboratory AECOM

The effect of the anion in the original rare earth element（REE） solution on the reversible ion exchange of Ce nitrate and Ce sulfate with the dowex 50 W X8 was investigated using attenuated total reflection infrared（ATR-IR） spectroscopy, continuous flow reactor studies coupled with inductively coupled plasma mass spectroscopy（ICP-MS）, and density functional theory（dFT）. The simulated IR spectrum at the dFT B3 LYP/6-31 G（d） level was compared to the experimental results to characterize the IR spectrum, molecular interactions, and bonding of the ion exchanged species. The continuous liquid flow reactor studies show a capacity of 0.72 mmol/g sorbent for the Ce nitrateand 0.96 mmol/g sorbent for the Ce sulfate with the dowex 50 W X8. The flow reactor studies reveal the type of solute anion（SO_4^（（2-）） or NO_3^（（-））） associated with the REE during cation exchange significantly affects the sorption capacity of the dowex 50 W X8 ion exchange resin. The calculated REE binding energy（BE） and the dFT optimized structures suggest that the differences in sorption capacity is the result of the formation of different types of partially ionexchanged Ce_2^（（3＋））2 SO_4^（（2-）） and Ce^（（3＋）） 3 NO_3^（（-））. These results suggest that the solute anion affects the equilibrium constants of the dowex resin by the formation of a charged layer capable of retaining the counterion. Modifying the sulfonic acid site（H＋） in the dowex 50 W X8 with the NH_4~＋ counterion does not affect the sorption capacity and retention times of the Ce nitrate and Ce sulfate species. These results suggest that the counterions and co-ions having a finite size, may limit access to the dowex sulfonate active site where the type of REE cation as a nitrate or sulfate in solution may significantly modify the sorption capacity of the ion exchange resin. Similar results are obtained during sorption with nitrates and sulfates of Sm and Yb.

关键词： Ion exchange dowex Anion effects Rare earth metal sorption

The role of vitamin d in cancer prevention

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Chinese Journal of Natural Medicines 2015年第7期13卷 481-497页

作者： Rachel A.Ness duane d.Miller Wei LI department of Pharmaceutical Sciences University of Tennessee Health Sciences Center

Vitamin d,also known as cholecalciferol,is the precursor to the active steroid hormone 1,25-dihydroxyvitamin d3(calcitriol; 1,25(OH)2d3).The main physiological role for 1,25(OH)2d3 is to regulate calcium and inorganic phosphate homeostasis for bone *** recently,vitamin d has been investigated for its effects in the prevention and treatment of a variety of diseases such as cancer,autoimmune disorders,and cardiovascular *** data strongly support a role for vitamin d in the prevention of cancer through its anti-proliferative,pro-apoptotic,and anti-angiogenic effects on *** and clinical studies have shown mixed data on the correlation between serum vitamin d levels and cancer *** report seeks to outline results from the most recent preclinical and clinical studies investigating the potential role of vitamin d in cancer prevention.

关键词： Vitamin d Calcitriol Cancer prevention Cancer prognosis Vitamin d deficiency

A Ca^(2+) cycling defect connects insulin resistance and heart failure

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Life Metabolism 2022年第1期1卷 2-3页

作者： Qian Shi duane d.Hall Long-Sheng Song division of Cardiovascular Medicine Department of Internal MedicineAbboud Cardiovascular Research CenterCarver College of MedicineUniversity of IowaIowa CityIA 52242USA

In a recent study published in Life Metabolism,Quan et *** that intracellular Ca^(2+)dysregulation in cardiomyocyte can be both a cause and an effect of cardiac insulin resistance that ultimately leads to diabetic *** epidemiologic studies across several decades indicate that insulin-resistant states such as diabetes and obesity are risk factors for congestive heart failure independent of common cardiovascular disease factors such as hypertension and coronary artery diseases[1,2].On the other hand,there is evidence that heart failure itself causes the onset and development of insulin resistance[3].Restoring normal cardiac output in advanced heart failure patients with left ventricular assistance devices improves insulin sensitivity and cardiac metabolism[4].

关键词： metabolism cardiac al.

Fuzzy control of electro-mechanical gearbox actuator

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中南大学学报（自然科学版） 2003年第Z1期34卷 113-117页

作者： G Iordanidis P H mellor d Holliday P M Churn department of Electrical and Electronic Engineering University of Bristol Bristol BS8 1UB UK

In this paper, a prototype direct-drive electro-mechanical actuator is proposed to select gears in a high performance gearbox. Because of the nonlinear behavior of the actuator, a fuzzy logic controller is adopted. The result of simulation has proved that the dynamic response obtained using the fuzzy controller is much faster than that obtained using traditional Pd controller.

关键词： actuator Pd controller fuzzy logic controller

Fifth-degree elastic energy for predictive continuum stress-strain relations and elastic instabilities under large strain and complex loading in silicon

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npj Computational Materials 2020年第1期6卷 697-704页

作者： Hao Chen Nikolai A.Zarkevich Valery I.Levitas duane d.Johnson Xiancheng Zhang Key Laboratory of Pressure Systems and Safety Ministry of EducationSchool of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai 200237China Ames Laboratory U.S.Department of EnergyIowa State UniversityAmesIA 50011-3020USA department of Aerospace Engineering Iowa State UniversityAmesIA 50011USA department of Mechanical Engineering Iowa State UniversityAmesIA 50011USA department of Materials Science&Engineering Iowa State UniversityAmesIA 50011USA

Materials under complex loading develop large strains and often phase transformation via an elastic instability,as observed in both simple and complex ***,we represent a material(exemplified for Si I)under large Lagrangian strains within a continuum description by a 5^(th)-order elastic energy found by minimizing error relative to density functional theory(dFT)results.

关键词： continuum energy minimizing

design of high-strength refractory complex solid-solution alloys

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npj Computational Materials 2018年第1期3卷 519-526页

作者： Prashant Singh Aayush Sharma A.V.Smirnov Mouhamad S.diallo Pratik K.Ray Ganesh Balasubramanian duane d.Johnson Ames Laboratory U.S.Department of EnergyIowa State UniversityAmesIA 50011USA Mechanical Engineering Iowa State UniversityAmesIA 50011USA Materials Science&Engineering Iowa State UniversityAmesIA 50011USA Mechanical Engineering&Mechanics Lehigh UniversityBethlehemPA 18015USA

Nickel-based superalloys and near-equiatomic high-entropy alloys containing molybdenum are known for higher temperature strength and corrosion ***,complex solid-solution alloys offer a huge design space to tune for optimal properties at slightly reduced *** refractory Mo-W-Ta-Ti-Zr,we showcase KKR electronic structure methods via the coherent-potential approximation to identify alloys over five-dimensional design space with improved mechanical properties and necessary global(formation enthalpy)and local(short-range order)*** is modeled with classical molecular dynamic simulations,validated from our first-principle *** predict complex solid-solution alloys of improved stability with greatly enhanced modulus of elasticity(3×at 300 K)over near-equiatomic cases,as validated experimentally,and with higher moduli above 500 K over commercial alloys(2.3×at 2000 K).We also show that optimal complex solid-solution alloys are not described well by classical potentials due to critical electronic effects.

关键词： alloys strength corrosion

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疑为细菌性脑膜炎时CT与腰穿的价值

国外医学（儿科学分册） 1993年第5期20卷 248-250页

作者： mellor d H. 夏经

急性细菌性脑膜炎(ABM)的病死率已显著降低,但由于颅高压致死的仍占ABM死亡中的30%。尽管ABM时不作腰穿亦可发生脑疝,但大多数死于脑病的患者均在腰穿后24小时内发生,提示脑脊液可持续通过硬脑膜穿刺裂隙而漏入硬膜外腔,故应慎重选择腰... 详细信息

急性细菌性脑膜炎(ABM)的病死率已显著降低,但由于颅高压致死的仍占ABM死亡中的30%。尽管ABM时不作腰穿亦可发生脑疝,但大多数死于脑病的患者均在腰穿后24小时内发生,提示脑脊液可持续通过硬脑膜穿刺裂隙而漏入硬膜外腔,故应慎重选择腰穿检查。CT在除外ABM合并颅内压升高的其它疾病,如颅后窝肿瘤、急性脑积水或颅内出血时很有价值,但无助于早期的脑疝诊断。短暂惊厥后30分钟,强直持续性惊厥(多示危重颅内高压),败血症休克或ABM有视乳头水肿时禁忌作腰穿,但不应延误其它的诊断检查和治疗。

关键词：脑膜炎脊椎穿刺 CT