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Investigation of Influencing Parameters for Tribological Conditions in Dry Forming Processes

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Acta Metallurgica Sinica(English Letters) 2015年第12期28卷 1435-1441页

作者： jennifer Steiner Marion Merklein Institute of Manufacturing Technology Friedrich-Alexander-Universitat Erlangen-Nürnberg

Environmental awareness and a growing demand for efficient resource utilization encourage the realization of lubricant-free forming processes. A first step in accomplishing dry sheet metal forming is to gain knowledge about the changing tribological conditions and to identify the relevant influencing parameters. The commonly used flat strip drawing test was selected to investigate the tribological conditions in the flange area of deep drawing processes. The influencing factors of contact pressure and varying drawing velocities were analyzed under dry and lubricated conditions. Additionally,the tool and workpiece surfaces were characterized. Besides lubrication, the contact pressure mainly determines the tribological conditions. In lubricated tests higher normal pressure reduces friction, whereas without lubrication higher pressure results in slightly increasing friction. A changing drawing velocity affects the friction when lubricant is applied. In dry experiments, no influence of velocity was found. Results of surface characterization reveal adhesion as main wear mechanism under dry conditions. Based on the investigated influence of the process parameters, an increase in process understanding for dry forming operations is derived.

关键词： Deep drawing Tribology Friction Dry forming

Nanostructure in energy conversion

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Journal of Energy Chemistry 2016年第2期25卷 169-188页

作者： Saskia Buller jennifer Strunk Max-Planck-Institute for Chemical Energy Conversion Mulheim Ruhr Germany Center for Nanointegration Duisburg-Essen University of Duisburg-Essen Germany

Nanostructured and nanosized materials are widely applied to tackle the pressing challenges associated with energy conversion. In this conceptual review, rather than highlighting separate examples, we aim to give a general overview about where and how nanostructure design can be beneficial in the three major research fields（photo）thermal chemical energy conversion, electrochemical energy conversion, and solar energy conversion. It will be shown that in many cases the design of catalytically active nanostructures is the main task and that especially for catalysts nanostructure and activity are inseparably linked to each other. Moreover, electrochemical and photochemical processes are complicated by the overlap of multiple processes that all need to be optimized, including in particular light absorption, charge migration,recombination and trapping events and surface processes. It will also be shown how the development of materials for new challenges can often be based on our knowledge on existing materials for related applications.

关键词： Renewable energy Nanostructure Electrochemical energy Solar power

A Randomized Controlled Trial of Mindfulness in Recovery from Colorectal Cancer

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Chinese Journal of Integrative Medicine 2023年第7期29卷 590-599页

作者： Andrew McCombie jennifer Jordan Roger Mulder Kishion Dee Ee Lin Ong Fernanda Fernandez Zimmermann Chris Frampton Frank Frizelle Te Whatu Ora(Health New Zealand)Waitaha Canterbury Christchurch 8011New Zealand University of Otago Christchurch 8140New Zealand The Psychology Hub Christchurch 8011New Zealand Oxford Mindfulness Centre University of OxfordOxfordOX12JDUnited Kingdom Nature and Nurture Sparks Christchurch 8013New Zealand University of Otago Dunedin(9016)New Zealand

Objective:This study examined whether a 4-week group-based mindfulness intervention would be superior in reducing psychological distress in colorectal cancer(CRC)patients compared to a psychoeducation and cognitive behavioural skills learning support active control ***:Patients with CRC were randomized via Computerised Permuted Block Randomisation to mindfulness or active control groups(2-h weekly sessions over 4 weeks).Outcomes were measured pre-intervention,and 8 weeks and 6 months *** primary outcome was psychological distress measured by the Hospital Anxiety and Depression *** outcomes were generic quality of life(QoL),disease specific QoL,mindfulness,and intervention credibility and ***:Sixty-eight participants were randomized to mindfulness(n=35)or active control group(n=33).Uptake of potentially eligible patients consenting was low(28.0%)and the dropout rate was 33.8%.Depression scores were reduced in both groups at week 8(P=0.020).Control participants had greater improvement in generic mental QoL scores at week 8 than mindfulness(P=0.023).In disease specific QoL,there was reduction in impotence symptom in the mindfulness group(P=0.022)and reduction in faecal incontinence in the control group(P=0.019).The embarrassment symptom had a significantly lower increase in the mindfulness group at week 8 compared to the control group(P=0.009).Both groups rated the treatments as credible and ***:Mindfulness was not superior to the active control group in terms of alleviating psychological distress but both treatments were associated with some improvements in *** was low uptake of both interventions.(Trial registration number:ACTRN12616001033437)

关键词： anxiety colorectal cancer depression distress mindfulness psychoeducation psychology psychological distress randomized controlled trial quality of life

Ultraviolet light exposure and its penetrance through the eye in a porcine model

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International Journal of Ophthalmology(English edition) 2023年第2期16卷 172-177页

作者： Hideki Fukuoka Helena E.Gali jennifer J.Bu Ruti Sella Natalie A.Afshari Shiley Eye Institute Viterbi Family Department of OphthalmologyUniversity of California San DiegoLa JollaCA 92093USA

AIM:To determine the amount of ultraviolet(UV)light irradiance that various layers of the eye receive as sunlight passes through the eye,and to investigate the protective benefits of UV light-blocking contact ***:Twenty-four porcine eyes were prepared in one of three ways:isolated cornea,cornea and lens together,or whole eye *** light irradiance was measured with a UV-A/B light meter before and after the eye preparations were placed over the meter to measure UV light penetration in each eye *** the whole eye preparation,a hole was placed in the fovea to measure light as it passed through the ***,UVprotective contact lenses were placed over the structures,and UV light penetrance was *** of UV light exposure were taken outdoors at various locations and ***:Cornea absorbed 63.56%of UV light that reached the *** and lens absorbed 99.34%of UV *** eye absorbed 99.77%of UV *** UV-protective contact lenses were placed,absorption was 98.90%,99.55%,and 99.87%,*** light exposure was dependent on directionality and time of day,and was greatest in areas of high albedo that reflect significant amounts of light,such as a ***:Cornea absorbs the majority of UV light that reaches the eye in this ***-protective contact lenses reduce UV exposure to the *** with high albedo expose the eye to higher levels of UV light.

关键词： ultraviolet light penetrance contact lens cornea lens

Tuning the crystal structure and optical properties of selective area grown InGaAs nanowires

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Nano Research 2022年第4期15卷 3695-3703页

作者： Zahra Azimi Aswani Gopakumar Amira SAmeruddin Li Li Thien Truong Hieu TNguyen Hark Hoe Tan Chennupati Jagadish jennifer Wong-Leung Department of Electronic Materials Engineering Research School of PhysicsThe Australian National UniversityCanberra ACT 2601Australia Faculty of Applied Science and Technology Universiti Tun Hussein Onn MalaysiaBatu Pahat 86400Malaysia Australian National Fabrication Facility ACT Node Research School of PhysicsThe Australian National UniversityCanberra ACT 2601Australia School of Engineering The Australian National UniversityCanberra ACT 2601Australia Australian Research Council Centre of Excellence for Transformative Meta-Optical Systems Research School of PhysicsThe Australian National UniversityCanberra ACT 2601Australia

Catalyst-free InGaAs nanowires grown by selective area epitaxy are promising building blocks for future optoelectronic devices in the infrared spectral *** progress,the role of pattern geometry and growth parameters on the composition,microstructure,and optical properties of InGaAs nanowires is still ***,we present an optimised growth parameter window to achieve highly uniform In1-xGaxAs nanowire arrays on GaAs(111)B substrate over an extensive range of Ga concentrations,from 0.1 to 0.91,by selective-area metal-organic vapor-phase *** observe that the Ga content always increases with decreasing In/(Ga+In)precursor ratio and group V flow rate and increasing growth *** increase in Ga content is supported by a blue shift in the photoluminescence peak *** geometry of the nanowire arrays also plays an important role in the resulting ***,increasing the nanowire pitch size from 0.6 to 2μm in a patterned array shifts the photoluminescence peak emission by up to 120 *** of these growth and geometry parameters,the Ga content determines the crystal structure,resulting in a predominantly wurtzite structure for xGa≤0.3 and a predominantly zinc blende phase for xGa≥*** insights on the factors controlling the composition of InGaAs nanowires grown by a scalable catalyst-free approach provide directions for engineering nanowires as functional components of future optoelectronic devices.

关键词： InGaAs nanowires ternary semiconductors selective-area metal-organic vapor-phase epitaxy nanostructure pattern geometry

Trends in characteristics of neurologists who provide stroke consultations in the USA,2008-2021

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Stroke & Vascular Neurology 2023年第1期8卷 86-88页

作者： Carter H Nakamoto Andrew D Wilcock Lee H Schwamm jennifer J Majersik Kori S Zachrison Ateev Mehrotra Department of Health Care Policy Harvard Medical SchoolBostonMassachusettsUSA Department of Family Medicine University of Vermont Larner College of MedicineBurlingtonVermontUSA Department of Neurology Massachusetts General HospitalBostonMassachusettsUSA Department of Neurology University of UtahSalt Lake CityUtahUSA Department of Emergency Medicine Massachusetts General HospitalBostonMassachusettsUSA Division of General Medicine and Primary Care Beth Israel Deaconess Medical CenterBostonMassachusettsUSA

Introduction Patients with acute ischaemic strokes(AIS),on average,fare better with timely neurologist consultation,and a growing proportion of them receive ***,little is known about trends in the characteristics of neurologists who treat *** We identified AIS and transient ischaemic attack(TIA)episodes with neurologist consults in fee-for service Medicare from January 2008 to September *** each episode,we determined whether the neurologist was a vascular neurologist,was a high-volume provider,whether the patient was transferred between hospitals and the distance between the patient’s home and physician’s *** From 2008 to 2021,the share of AIS/TIA episodes(n=5073294)with neurologist consults increased(52.9%to 61.7%).Among episodes with consults,the fraction conducted by a vascular neurologist(5.2%to 13.7%)or by a high-volume neurologist(13.2%to 14.9%)also *** fraction with the patient’s home and neurologist greater than 100 miles apart(4.8%to 9.6%)or in different states(5.1%to 8.1%)increased,as did the fraction with transfers(4.2%to 8.5%).Discussion Over the study period,the proportion of AIS/TIA episodes with consultations from neurologists with either vascular neurology certifications or high volumes increased substantially.

关键词： acute characteristics consultation

Klotho and neurons: mutual crosstalk between autophagy, endoplasmic reticulum, and inflammatory response

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Neural Regeneration Research 2021年第8期16卷 1542-1543页

作者： jennifer Mytych Department of Animal Physiology and Reproduction Institute of Biology and BiotechnologyCollegium Scientarium NaturaliumUniversity of RzeszowWerynia 236-100 KolbuszowaPoland

Klotho is one of a number of well-known longevity-associated *** depletion in aging or disease may promote several neuropathologies associated with the central nervous system,including hypomyelination and phosphorylat... 详细信息

关键词： Klotho inflammation reticulum

Entrainment of *** and Listeria monocytogenes from sediment in irrigation canal

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International Journal of Sediment Research 2022年第6期37卷 701-714页

作者： Kun Qi Erfan Ghasemi Tousi jennifer Guohong Duan Patricia Marie Gundy Kelly Rae Bright Charles Peter Gerba Department of Civil & Architectural Engineering and Mechanics The University of Arizona Department of Environmental Science The University of Arizona Water & Energy Sustainable Technology (WEST) Center

E. coli and Listeria monocytogenes(or L. monocytogenes) are bacteria affecting fresh produce that is harmful for health of humans and animals. If these bacteria are present in surface waterbody(e.g.,irrigation canals), they will impair irrigation water quality and threaten produce safety. This paper studied the resuspension of E. coli and Listeria from bed sediment into irrigation water through several sets of laboratory experiments in an open channel flume. We studied three types of sediments using several flow rates in different velocities and shear stress. Bacteria’s concentration in water increases with the bed shear stress. Two empirical relations were derived to correlate the concentration of E. coli and L. monocytogenes with the dimensionless bed shear stress. The experimental data favorably verified the relationships for sandy loam, loamy sand, and loam. The results showed that both bacteria could entrain from sand more efficiently compared to other sediments(i.e., sandy loam or loam). These relationships can be applied to water quality models for simulating E. coli and L. monocytogenes transport in irrigation canals for better managing irrigation water quality.

关键词： Bacteria E. coli L. monocytogenes Sediment transport Irrigation water Sediment model

Turbulent burst around experimental spur dike

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International Journal of Sediment Research 2011年第4期26卷 471-486+523页

作者： jennifer DUAN Department of Civil Engineering and Engineering Mechanics University of Arizona

Three-dimensional turbulent flow field was measured around an experimental spur dike by using a micro-acoustic Doppler *** fractions of turbulent burst events including outward interaction,ejection,inward interaction,and sweep were analyzed in each quadrant at the neighbor of the dike before and after the formation of scour *** 80%of burst events near the bed have lower-order of magnitudes for both flat and scoured bed *** and sweeps are prevalent before the local scour was initiated,and then outward interactions are dominant after the scour hole was *** Reynolds stresses and high-order moments of turbulent velocities were analyzed along the *** magnitudes of u’-w’ pair were much larger than those of v’-vv’ pair in the scour *** four burst events,ejections and sweeps are the higher order events contributing to the Reynolds *** sediment entrainment and transport are closely associated with turbulent bursts near bed,the development of scour hole greatly depends on the higher order event near the bed.

关键词： Turbulent burst Spur dike Quadrant analysis High-order momentums