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Micron-gap spacers with ultrahigh thermal resistance and mechanical robustness for direct energy conversion Samuel

Microsystems & Nanoengineering 2019年第1期5卷 344-355页

作者： M.Nicaise Chen Lin Mohsen Azadi Tara Bozorg-Grayeli Promise Adebayo-Ige Drew E.Lilley Yann Pfitzer Wujoon Cha Kyana Van Houten nicholas a.melosh Roger T.Howe Jared W.Schwede Igor Bargatin Mechanical Engineering and Applied Mechanics University of PennsylvaniaPhiladelphiaPA 19104USA Materials Science&Engineering Stanford UniversityStanford 94305 CAUSA Chemical and Biomolecular Engineering University of PennsylvaniaPhiladelphiaPAUSA Spark Thermionics BerkeleyCA 94720USA Electrical Engineering Stanford UniversityStanfordCA 94305USA

In thermionic energy converters,the absolute efficiency can be increased up to 40%if space-charge losses are eliminated by using a sub-10-μm gap between the *** practical way to achieve such small gaps over large device areas is to use a stiff and thermally insulating spacer between the two *** report on the design,fabrication and characterization of thin-film alumina-based spacers that provided robust 3–8μm gaps between planar substrates and had effective thermal conductivities less than those of *** spacers were fabricated on silicon molds and,after release,could be manually transferred onto any *** large-scale compression testing,they sustained compressive stresses of 0.4–4 MPa without ***,the thermal conductance was 10–30 mWcm^(−2)K^(−1)and,surprisingly,independent of film thickness(100–800 nm)and spacer *** explain this independence,we developed a model that includes the pressure-dependent conductance of locally distributed asperities and sparse contact points throughout the spacer structure,indicating that only 0.1–0.5%of the spacerelectrode interface was conducting *** spacers show remarkable functionality over multiple length scales,providing insulating micrometer gaps over centimeter areas using nanoscale *** innovations can be applied to other technologies requiring high thermal resistance in small spaces,such as thermophotovoltaic converters,insulation for spacecraft and cryogenic devices.

关键词： thermal resistance film

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热增强的光电化学反应

热增强的光电化学反应

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2019第四届中国能源材料化学研讨会

作者：张黎明 Xiaofei Ye Madhur Boloor nicholas a.melosh William C.Chueh 复旦大学化学系斯坦福大学材料科学与工程系

过渡金属氧化物具备较高的化学稳定性,是一大类广泛应用的光阳极材料,其缺点在于低迁移率（10-1-10-4cm2V-1s-1）直接制约了氧化物中光生少数载流子的扩散长度,导致光电流低下。实现光生少数载流子的有效收集是提升太阳能人工光合成制... 详细信息

过渡金属氧化物具备较高的化学稳定性,是一大类广泛应用的光阳极材料,其缺点在于低迁移率（10-1-10-4cm2V-1s-1）直接制约了氧化物中光生少数载流子的扩散长度,导致光电流低下。实现光生少数载流子的有效收集是提升太阳能人工光合成制的燃料的效率所面临的关键科学问题。对于过渡金属氧化物,其载流子输运遵循"小极化子跃迁"模式,即载流子的迁移率随温度升高呈指数增长。针对这一特征,我们以钒酸铋为研究体系,首次阐明了升高温度对氧化物半导体光催化水分解反应的增强作用,当温度从10℃升高至42℃,光电流增长2.2倍,实现了燃料制备效率的显著提高。我们通过比较温度对多种氧化物半导体水分解反应的影响,揭示了光生少数载流子扩散长度随温度的增加是水分解效率增强的主导性因素,并发展了利用光电流的温度效应测量少数载流子跃迁活化能和扩散长度的方法。最后,我们以钒酸铋半导体为研究对象,结合固相离子导体,构筑了高温全固相光电化学反应器件。

关键词：人工光合成太阳能转化热增强效应水分解钒酸铋

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PROJECT MANAGEMENT:RECENT DEVELOPMENTS AND RESEARCH OPPORTUNITIES

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Journal of Systems Science and Systems Engineering 2012年第2期21卷 129-143页

作者： nicholas G.HALL Department of Management Sciences Fisher College of Business The Ohio State UniversityUSA

This paper studies the business process known as project management. This process has exhibited a remarkable growth in business interest over the last 15 years, as demonstrated by a 1000% increase in membership in the Project Management Institute since 1996. This growth is largely attributable to the emergence of many new diverse business applications that can be successfully managed as projects. The new applications for project management include IT implementations, research and development, new product and service development, corporate change management, and software development. The characteristics of modem projects are typically very different from those of traditional projects such as construction and engineering, which necessitates the development of new project management techniques. We discuss these recent practical developments. The history of project management methodology is reviewed, from CPM and PERT to the influential modem directions of critical chain project management and agile methods. We identify one important application area for future methodological change as new product and service development. A list of specific research topics within project management is discussed. The conclusions suggest the existence of significant research opportunities within project management.

关键词： Project management overview recent practical developments opportunities for research

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The formation of massif anorthosite:Petrology in reverse

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Geoscience Frontiers 2013年第2期4卷 195-198页

作者： nicholas Arndt ISTerre Universite Joseph Fourier:UMR5275CNRS1381 rue de la Piscine38400 St Martin d'HeresFrance

Massif anorthosites form when basaltic magma differentiates in crustal magma chambers to form lowdensity plagioclase and a residual liquid whose density was greater than that of enclosing crustal rocks. The plagioclase and minor pyroxene crystallized in-situ on the floor of the magma chamber to produce the anorthosite complex,and the residual liquid migrated downwards,eventually to solidify as dense Fe-rich cumulates some of which were removed to the *** movements were facilitated by high temperatures in Proterozoic continental crust,thus explaining the restriction of large anorthosite massifs to this period in Earth history.

关键词： Anorthosite Petrology Proterozoic

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Composites with high omnidirectional fracture toughness due to helical interlocking fasteners are found in gingko seed shells

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National Science Review 2023年第5期10卷 106-108页

作者： nicholas A.Kotov Department of Chemical Engineering Biointerfaces InstituteDepartment of Materials Science and EngineeringUniversity of Michigan Department of Aeronautics Imperial College London

Engineering of composites mimicking load-bearing materials from living organisms is essential for sustainable economic development and successful resolution of current and future bottle-necks of chemical,automotive,av...

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Murine study of portal hypertension associated endothelin-1 hypo-response

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World Journal of Gastroenterology 2015年第16期21卷 4817-4828页

作者： nicholas Theodorakis Mary Maluccio nicholas Skill Department of Surgery Division of Transplant SurgeryIndiana School of MedicineIndiana University

AIM:To investigate endothelin-1 hypo-responsive associated with portal hypertension in order to improve patient treatment ***:Wild type,e NOS-/-and i NOS-/-mice receivedpartial portal vein ligation surgery to induce portal hypertension or sham *** of portal hypertension was determined by measuring the splenic pulp pressure,abdominal aortic flow and portal systemic *** measure splenic pulp pressure,a microtip pressure transducer was inserted into the spleen *** aortic flow was measured by placing an ultrasonic Doppler flow probe around the abdominal aorta between the diaphragm and celiac *** systemic shunting was calculated by injection of fluorescent microspheres in to the splenic vein and determining the percentage accumulation of spheres in liver and pulmonary ***-1 hypo-response was evaluated by measuring the change in abdominal aortic flow in response to endothelin-1 intravenous *** addition,thoracic aorta endothelin-1contraction was measured in 5 mm isolated thoracic aorta rings ex-vivo using an ADI small vessel ***:In wild type and i NOS-/-mice splenic pulp pressure increased from 7.5±1.1 mm Hg and 7.2±1 mm Hg to 25.4±3.1 mm Hg and 22±4 mm Hg *** e NOS-/-mice splenic pulp pressure was increased after 1 d(P=NS),after which it decreased and by 7 d was not significantly elevated when compared to 7 d sham operated controls(6.9±0.6 mm Hg and 7.3±0.8 mm Hg respectively,P=0.3).Abdominal aortic flow was increased by 80%and 73%in 7 d portal vein ligated wild type and i NOS when compared to shams,whereas there was no significant difference in 7 d portal vein ligated e NOS-/-mice when compared to ***-1 induced a rapid reduction in abdominal aortic blood flow in wild type,e NOS-/-and i NOS-/-sham mice(50%±8%,73%±9%and 47%±9%respectively).Following portal vein ligation endothelin-1 reduction in blood flow was significantly diminished in each mouse group

关键词： Liver disease Portal hypertension Hyperdynamiccirculation Endothelin-1 Nitric oxide synthaseisoforms

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Longitudinal bicyclist,driver,and pedestrian perceptions of autonomous vehicle communication strategies

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Journal of Traffic and Transportation Engineering(English Edition) 2023年第1期10卷 31-44页

作者： nicholas N.Ferenchak Department of Civil Construction&Environmental EngineeringUniversity of New MexicoAlbuquerqueNM 87131USA

We sought to better understand how autonomous vehicle(AV)communication strategies impact human road users’*** specifically,we explored the impact of different external human-machine interface(eHMI)designs on task load,comfort,trust,and *** accomplish this,we created virtual reality(VR)scenarios where human participants interacted with AVs in biking,driving,and pedestrian *** were brought back after initial testing to explore acclimation and learning *** designs included a text-based grille eHMI,a text-based roof eHMI,a text-based driver-side door eHMI,anon-textual LED windshield strip eHMI,and a non-textual side mirror arrow *** presence of an eHMI was the strongest positive predictor of comfort,trust,and acceptance outcomes in the statistical models when controlling for all other *** was a clear divide between text-based eHMIs and non-text eHMIs with text-based eHMIs experiencing better perception *** LED Windshield experienced the worst perception *** were perception acclimation effects detected which were most notable for task load(which decreased over time)and comfort(which increased over time).Perception scores for the different eHMI designs tended to cluster over ***,the acclimation effects had less of an impact than the presence of an *** outcomes had weaker relationships with participant characteristics than with AV *** suggest that eHMI presence and design,AV behavior,and acclimation are most impactful in terms of perceptions.

关键词： Vehicle automation Communication Human-automation interaction Technology acceptance Virtual reality

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Nonlinear Model of Mean Free Surface of Waves

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China Ocean Engineering 1999年第2期14卷 155-162页

作者： nicholas DODD Ph. D. Coastal Group HR Wallingford Howbery Park Wallingford

A nonlinear model of mean free surface of waves or wave set-up is presented. The model is based on that of Roelvink (1993), but the numerical techniques used in the solution are based on the Weighted-Average Flux (WAF) method (Watson el al., 1992), with Time-Operator-Splitting (TOS) used for the treatment of the source terms. This method allows a small number of computational points to be used, and is particularly efficient in modeling wave set-up. The short wave (or primary wave) energy equation is solved by use of a more traditional Lax-Wendroff technique. A nonlinear wave theory (James, 1974) is introduced. The model described in this paper is found to be satisfactory in most respects when compared with the measurements conducted by Stive (1983) except in modeling the mean free surface very close to the mean shoreline.

关键词： mean free surface radiation stress hyperbolic wave theory nonlinear model wave propagation

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Do neuronal microvascular activation and resultant dysfunction in rheumatoid arthritis contribute to chronic pain?

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Neural Regeneration Research 2019年第1期14卷 79-81页

作者： nicholas Beazley-Long Arthritis Research UK Pain Centre & School of Life Sciences Medical School University of Nottingham

Microvascular dysfunction and rheumatoid arthritis(RA):Across the UK severe osteoarthritis affects～5–7%and RA affects～1%of the *** are the most common causes of disabling chronic pain and are major burdens on individuals and ***,the annual financial cost to the UK economy for arthritis is in the billions of *** living with painful inflammatory conditions and

关键词：风湿性关节炎机能障碍疼痛激活骨关节炎心血管糖尿病 RA

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Analytical model for predicting folding stable state of bistable deployable composite boom

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Chinese Journal of Aeronautics 2024年第8期37卷 460-469页

作者： Tianwei LIU Jiangbo BAI nicholas FANTUZZI School of Transportation Science and Engineering Beihang UniversityBeijing 100191China Jingdezhen Research Institute of Beihang University Jingdezhen 333000China DICAM Department University of BolognaBologna 40136Italy

Bistable Deployable Composite Boom(Bi-DCB)can achieve bistable function by storing and releasing strain energy,which has a good application prospect in space *** example,it serves as the main support section of deployable structures(e.g.,solar arrays and antennas).This paper investigates folding stable state of Bi-DCB through the analytical *** on Archimedes’helix and energy principle,an analytical model for predicting folding stable state of Bi-DCB was *** failure index of Bi-DCB in folding stable state were analyzed using the Tsai-Hill criterion and the maximum stress ***,a 2400 mm long Bi-DCB was fabricated using autoclave *** prediction results of the proposed model were compared with experiments and results of two other analytical *** is shown that the proposed model shows good prediction ***,the effect of geometric parameters on folding stable state of Bi-DCB was further investigated with the aid of the proposed model.

关键词： Bistable Deployable composite boom Solar arrays Antennas Archimedes’helix Folding Failure analysis

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