Strain-controlled Graphene-Polymer Angular Actuator

MRS Advances ◽  
2019 ◽  
Vol 4 (40) ◽  
pp. 2161-2167
Author(s):  
S. Matt Gilbert ◽  
Adam Molnar ◽  
Donez Horton-Bailey ◽  
Helen Y. Yao ◽  
Alex Zettl
Keyword(s):  
Electron Microscope ◽  
Elastic Modulus ◽  
Scanning Electron Microscope ◽  
Methyl Methacrylate ◽  
Angular Displacement ◽  
Suspended Graphene ◽  
Entire Structure ◽  
Central Disc ◽  
Pmma Polymer ◽  
Scanning Electron

ABSTRACTWe demonstrate a suspended graphene-(poly(methyl methacrylate) (PMMA) polymer angular displacement actuator enabled by variable elastic modulus of the perforated stacked structure. Azimuthal flexures support a central disc-shaped membrane, and compression of the membrane can be used to control the rotation of the entire structure. Irradiating the PMMA on graphene stack with 5 kV electrons in a convention scanning electron microscope reduces the elastic modulus of the PMMA and allows graphene’s built in strain to dominate and compress the flexures, thus rotating the actuator.

Mechanism of Large Elastic Modulus of Bone

2011 ◽  
Vol 689 ◽  
pp. 390-394 ◽  
Author(s):  
Bin Chen ◽  
Da Gang Yin ◽  
Ji Luo ◽  
Quan Yuan ◽  
Jing Hong Fan
Keyword(s):  
Electron Microscope ◽  
Elastic Modulus ◽  
Scanning Electron Microscope ◽  
Large Volume ◽  
Volume Fraction ◽  
Thin Fiber ◽  
Sem Observation ◽  
Large Volume Fraction ◽  
Composite Mechanics ◽  
Scanning Electron

Scanning electron microscope (SEM) observation shows that fibula bone is a kind of bioceramic composite consisting of hydroxyapatite layers and protein matters. The hydroxyapatite layers are further composed of hydroxyapatite sheets. The observation also shows that the hydroxyapatite sheets possess quite large volume fraction and also have very long and thin fiber shape. The mechanism of the large volume fraction of the hydroxyapatite sheets to ensure the larger elastic modulus of the bone was investigated based on the model of the bone composite and the theory of the composite mechanics. The investigated result reveals that the large volume fraction of the hydroxyapatite sheets endows the bone with large elastic modulus.

Lung lymphatics cast from the airspace

1994 ◽  
Vol 267 (2) ◽  
pp. L199-L205 ◽  
Author(s):  
K. D. Hainis ◽  
J. I. Sznajder ◽  
D. E. Schraufnagel
Keyword(s):  
Electron Microscope ◽  
Lung Injury ◽  
Scanning Electron Microscope ◽  
Light Microscopy ◽  
Methyl Methacrylate ◽  
Three Dimensional ◽  
Ambient Air ◽  
Pleural Surface ◽  
Hyperoxic Lung Injury ◽  
Scanning Electron

Lymphatics are important in the resolution of pulmonary edema, but which lymphatics drain alveolar fluid and how they change during lung injury and edema is uncertain. To study this question 16 rats were exposed to 85% O2 for 7 days. At 0, 3, 7, and 14 days after removal from the hyperoxic chamber, the lungs of the rats were cast by instilling methyl methacrylate into the trachea. The lungs of four similar room-air breathing rats served as controls. Tissue was taken for light microscopy and the casts were examined for lymphatic filling with a scanning electron microscope. Rats exposed to hyperoxia had diffuse damage and extensive edema. On removal from hyperoxia (day 0), 29% of the rat bronchioles had saccular lymphatic casts around them and 6% of bronchioles were surrounded by these lymphatics. Twenty-five percent of bronchioles had conduit lymphatic casts. Fourteen percent of arteries had lymphatic casts around them. All were different from the rats kept in room air (P < 0.0001). Rats exposed to hyperoxia had lymphatics on the pleural surface, near alveoli and alveolar ducts, and around veins. The peribronchial and periarterial saccular lymphatics formed separate groups with communicating conduit lymphatics. The perivenous lymphatics had their own separate conduit lymphatics. Fourteen days after returning to ambient air, the lymphatics were similar to those of control animals. In this model, airway casting allows three-dimensional analysis of the lung lymphatics. It shows that lymphatic compartments expand during hyperoxic lung injury and that peribronchial and perivascular saccular lymphatics connect to conduit lymphatics of the bronchoalveolar bundle.

Scale effect investigation of copper microwire's mechanical properties after in situ scanning electron microscope twisting

2018 ◽  
Vol 233 (10) ◽  
pp. 3670-3677
Author(s):  
Fengmei Xue ◽  
Haojian Lu ◽  
Yajing Shen
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Elastic Modulus ◽  
Scanning Electron Microscope ◽  
Strain Hardening Exponent ◽  
Surface Cracks ◽  
Manipulation System ◽  
Fracture Features ◽  
Scanning Electron

In this study, the mechanical property of copper microwire, a widely used material in our daily life, is investigated by subjecting it to in situ scanning electron microscope twisting based on a self-developed nanorobotic manipulation system. First, copper microwire is assembled on the nanorobotic system inside the scanning electron microscope, and then twisted clockwise and anticlockwise continuously from 0° to 360° until fracture. After that, the mechanical properties of elastic modulus, microhardness, yield stress, and the strain hardening exponent of the twisted sample are investigated by nanoindentation. The change in elastic modulus and indention hardness showed strong indentation size effects, because a large number of geometrically necessary dislocations were generated around the indenter. In addition, the fracture analysis indicated that the smaller the scale of the material, the more sensitive it was to surface cracks or defects. Ductile fracture features of the twisted sample appear due to the nucleation, growth, and coalescence of the microvoids.

scholarly journals Production and Investigation of New Cast Aluminium Alloy with Lithium Addition

2020 ◽  
Vol 67 (1) ◽  
pp. 13-19
Author(s):  
Bastri Zeka ◽  
Boštjan Markoli ◽  
Primož Mrvar ◽  
Blaž Leskovar ◽  
Mitja Petrič
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Elastic Modulus ◽  
Scanning Electron Microscope ◽  
Natural Ageing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reduced Density ◽  
New Phase ◽  
Scanning Electron

AbstractLithium additions to Al offer the promise of substantially reducing the weight of alloys, since each 1 wt. % Li added to Al reduces density by 3 % and increases elastic modulus. In the present work, the effect of 1.46 wt. % Li addition to AlSi7Mg (containing 7.05 wt. % Si and 0.35 wt. % Mg) was studied. The alloy showed reduced density and higher hardness after natural ageing. Experimental work showed that micro-structural and mechanical properties changed with Li addition. It was observed that 0.80 wt. % Li addition resulted in formation of new phase AlLiSi which has a great effect to increase hardness of AlSi7Mg. According to Scanning Electron Microscope (SEM) and X-ray diffraction analysis it was confirmed that the addition of Li causes formation of different phases which are: α-Al, β-Si and AlLiSi.

Photoinitiated Emulsion Polymerization of P(MMA-co-DVB) Microspheres with Low Power Ultraviolet Light

2011 ◽  
Vol 194-196 ◽  
pp. 952-955
Author(s):  
Li Jun Tao ◽  
Feng Qiang Sun
Keyword(s):  
Fourier Transform ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Methyl Methacrylate ◽  
Emulsion Polymerization ◽  
Room Temperature ◽  
Uv Light ◽  
Polymerization System ◽  
Scanning Electron ◽  
Ultraviolet Lamp

Poly (methyl methacrylate-co-divinylbenzene) [P(MMA-co-DVB)] microspheres were first synthesized by a simple photoinitiated emulsion polymerization methods. In this polymerization system, MMA, DVB, AIBN, isopropanol and hexahydrobenzene constituted the oil phase, SDS acted as the stabilizer and an 8 W Ultraviolet lamp was employed as the light source. Under the irradiation of the UV light, AIBN could be decomposed to produce radicals and initiate the polymerization of MMA to produce P(MMA-co-DVB) microspheres.The morphologies and structures of the products were characterized by Fourier transform infrared spectroscope (FTIR),size distribution, scanning electron microscope (SEM). The average diameters of the spheres increased with the content of DVB. The research may provide a quick, green and facile room-temperature approach to prepare polymer microspheres.

Three-Dimensional Architecture of Blood Vessels Of Tendons Demonstrated by Corrosion Casts

HAND ◽  
1978 ◽  
Vol os-10 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Hitoshi Takasugi ◽  
Osamu Akahori ◽  
Kenji Nishihara ◽  
Kanya Tada
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Methyl Methacrylate ◽  
Blood Vessels ◽  
Muscle Fibre ◽  
Three Dimensional ◽  
Corrosion Casts ◽  
Casting Method ◽  
Scanning Electron ◽  
Made In

Summary Three-dimensional observation of the microcirculation of the tendon was readily and clearly demonstrated by preparing methyl methacrylate casts and observing them under the scanning electron microscope. In the muscles blood vessels made a network like a ladder surrounding every muscle fibre. The fibrous digital sheath had blood vessels made in a fine meshed cylinder. By microdissection of the vessels of the sheath the blood vessels of the vinculae and tendons were observed stereoscopically in relation to the peritendinous tissues. The casting method contributes to better understanding of vascular architecture of tendons.

The Alteration of the Pore Spaces in Sandstones

1973 ◽  
Vol 31 ◽  
pp. 210-211
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
The Other ◽  
Coarse Grained ◽  
Depositional Fabric ◽  
Soluble Components ◽  
Scanning Electron ◽  
Shape And Size

The pore spaces in sandstones are the result of the original depositional fabric and the degree of post-depositional alteration that the rock has experienced. The largest pore volumes are present in coarse-grained, well-sorted materials with high sphericity. The chief mechanisms which alter the shape and size of the pores are precipitation of cementing agents and the dissolution of soluble components. Each process may operate alone or in combination with the other, or there may be several generations of cementation and solution.The scanning electron microscope has ‘been used in this study to reveal the morphology of the pore spaces in a variety of moderate porosity, orthoquartzites.

The Broad Applications of the Scanning Electron Microscope

1969 ◽  
Vol 27 ◽  
pp. 20-21
Author(s):  
C. T. Nightingale ◽  
S. E. Summers ◽  
T. P. Turnbull
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Light Microscopy ◽  
Surface Topography ◽  
Great Depth ◽  
Resolving Power ◽  
Depth Of Field ◽  
Pictorial Representations ◽  
Scanning Electron

The ease of operation of the scanning electron microscope has insured its wide application in medicine and industry. The micrographs are pictorial representations of surface topography obtained directly from the specimen. The need to replicate is eliminated. The great depth of field and the high resolving power provide far more information than light microscopy.

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