scholarly journals 4D Thermomechanical metamaterials for soft microrobotics

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Qingxiang Ji ◽  
Johnny Moughames ◽  
Xueyan Chen ◽  
Guodong Fang ◽  
Juan J. Huaroto ◽  
...  
Keyword(s):  
Driving Force ◽  
Stimuli Responsive ◽  
Mechanical Behaviors ◽  
Temperature Changes ◽  
Materials Properties ◽  
Gray Tone ◽  
Micro Actuators ◽  
Controlled Motion ◽  
Physical Phenomena ◽  
Thermal Stimuli

AbstractMetamaterials have attracted wide scientific interest to break fundamental bounds on materials properties. Recently, the field has been extending to coupled physical phenomena where one physics acts as the driving force for another. Stimuli-responsive or 4D metamaterials have been demonstrated for thermo-elasticity, magneto-optics or piezo-electricity. Herein, a soft, ultra-compact and accurate microrobot is described which can achieve controlled motion under thermal stimuli. The system consists of an organized assembly of two functional structures: a rotational and a translational element. Both elements are designed basing upon the principle of the thermoelastic bilayer plate that bends as temperature changes. Samples are fabricated using gray-tone lithography from a single polymer but with two different laser writing powers, making each part different in its thermal and mechanical behaviors. Excellent motion-controllable, reversible and stable features in a dry environment are verified by simulations and experiments, revealing broad application prospects for the designed soft micro actuators.

Extracellular Proteins as Enterobacterial Thermometers

2003 ◽  
Vol 86 (1-2) ◽  
pp. 139-156 ◽  
Author(s):  
Robin J. Rowbury
Keyword(s):  
Thermal Stress ◽  
Heat Shock ◽  
Stress Responses ◽  
Direct Evidence ◽  
Experimental Studies ◽  
Extracellular Proteins ◽  
Temperature Changes ◽  
Induction Components ◽  
Cellular Components ◽  
Thermal Stimuli

Biological thermometers are cellular components or structures which sense increasing temperatures, interaction of the thermometer and the thermal stress bringing about the switching-on of inducible responses, with gradually enhanced levels of response induction following gradually increasing temperatures. In enterobacteria, for studies of such thermometers, generally induction of heat shock protein (HSP) synthesis has been examined, with experimental studies aiming to establish (often indirectly) how the temperature changes which initiate HSP synthesis are sensed; numerous other processes and responses show graded induction as temperature is increased, and how the temperature changes which induce these are sensed is also of interest. Several classes of intracellular component and structure have been proposed as enterobacterial thermometers, with the ribosome and the DnaK chaperone being the most favoured, although for many of the proposed intracellular thermometers, most of the evidence for their functioning in this way is indirect. In contrast to the above, the studies reviewed here firmly establish that for four distinct stress responses, which are switched-on gradually as temperature increases, temperature changes are sensed by extracellular components (extracellular sensing components, ESCs) i.e. there is firm and direct evidence for the occurrence of extracellular thermometers. All four thermometers described here are proteins, which appear to be distinct and different from each other, and on sensing thermal stress are activated by it to four distinct extracellular induction components (EICs), which interact with receptors on the surface of organisms to induce the appropriate responses. It is predicted that many other temperature-induced processes, including the synthesis of HSPs, will be switched-on following the activation of similar extracellular thermometers by thermal stimuli.

Azobenzene Crystal Polymorphism Enables Tuneable Photoinduced Deformation, Mechanical Behaviors and Photoluminescent Properties

2021 ◽  
Author(s):  
Yunhui Hao ◽  
Lei Gao ◽  
Xiunan Zhang ◽  
Rongli Wei ◽  
Ting Wang ◽  
...  
Keyword(s):  
Smart Materials ◽  
Molecular Crystals ◽  
Stimuli Responsive ◽  
Mechanical Behaviors ◽  
Crystal Polymorphism

Stimuli-responsive molecular crystals are fascinating for their potential as adaptive smart materials. However, achieving one crystal that could respond to multiple stimuli and perform multiple functionalities simultaneously is still challenging....

scholarly journals Irreversible temperature gating in trpv1 sheds light on channel activation

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Ana Sánchez-Moreno ◽  
Eduardo Guevara-Hernández ◽  
Ricardo Contreras-Cervera ◽  
Gisela Rangel-Yescas ◽  
Ernesto Ladrón-de-Guevara ◽  
...  
Keyword(s):  
Trp Channels ◽  
Structural Information ◽  
Heat Absorption ◽  
Absorption Process ◽  
Open Probability ◽  
Temperature Changes ◽  
Trpv1 Channels ◽  
Channel Opening ◽  
Temperature Activation ◽  
Thermal Stimuli

Temperature-activated TRP channels or thermoTRPs are among the only proteins that can directly convert temperature changes into changes in channel open probability. In spite of a wealth of functional and structural information, the mechanism of temperature activation remains unknown. We have carefully characterized the repeated activation of TRPV1 by thermal stimuli and discovered a previously unknown inactivation process, which is irreversible. We propose that this form of gating in TRPV1 channels is a consequence of the heat absorption process that leads to channel opening.

Diamond nano-optode for fluorescent measurements of pH and temperature

Nanoscale ◽  
2019 ◽  
Vol 11 (40) ◽  
pp. 18537-18542 ◽  
Author(s):  
Helena Raabova ◽  
David Chvatil ◽  
Petr Cigler
Keyword(s):  
Stimuli Responsive ◽  
Temperature Changes

Nano-optodes with a diamond core coated with a double stimuli-responsive polymeric shell reversibly respond to pH and temperature changes.

Local Temperature Determination Using Elfs Spectroscopy

1997 ◽  
Vol 3 (S2) ◽  
pp. 997-998
Author(s):  
M. Qian ◽  
M. Sarikaya ◽  
E. A. Stern
Keyword(s):  
Fine Structure ◽  
Local Temperature ◽  
Temperature Changes ◽  
Structure Information ◽  
Temperature Determination ◽  
Simultaneous Imaging ◽  
Quantitative Measurements ◽  
High Resolution Tem ◽  
Physical Phenomena ◽  
First Time

ELFS spectroscopy (energy loss fine structure) is used to obtain local atomic structure information It can outperform XAFS (x-ray absorption fine structure) not only because of its low Z element sensitivity, but also because of its high spatial resolution and the capability of combining other high resolution TEM measurements. Although TEM continues to gain importance as an indispensable and unique tool to study nanoscale phenomena by providing simultaneous imaging, diffraction, and spectroscopy information, direct observation and quantitative measurements of physical phenomena are also desirable. This paper gives a first-time demonstration of such a measurement, namely local temperature determination in a TEM sample by ELFS.The principle is simple and as follows. One can measure, with ELFS, the atomic distances up to ±0.01 Å accuracy for the fist shell (typically around 2 Å ) and the second shell (around 3-4 Å). Atomic distances in a sample will change when its temperature changes, the phenomena that are coupled by the macroscopic temperature dependent lattice expansion.

scholarly journals Atomically precise nanoclusters with reversible isomeric transformation for rotary nanomotors

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhaoxian Qin ◽  
Jiangwei Zhang ◽  
Chongqing Wan ◽  
Shuang Liu ◽  
Hadi Abroshan ◽  
...  
Keyword(s):  
Rational Design ◽  
Great Promise ◽  
Stimuli Responsive ◽  
Scanning Calorimetry ◽  
Isomeric Transformation ◽  
Wide Range ◽  
Intelligent Devices ◽  
Stimuli Response ◽  
Thermal Stimuli ◽  
Two Temperature

AbstractThermal-stimuli responsive nanomaterials hold great promise in designing multifunctional intelligent devices for a wide range of applications. In this work, a reversible isomeric transformation in an atomically precise nanocluster is reported. We show that biicosahedral [Au13Ag12(PPh3)10Cl8]SbF6 nanoclusters composed of two icosahedral Au7Ag6 units by sharing one common Au vertex can produce two temperature-responsive conformational isomers with complete reversibility, which forms the basis of a rotary nanomotor driven by temperature. Differential scanning calorimetry analysis on the reversible isomeric transformation demonstrates that the Gibbs free energy is the driving force for the transformation. This work offers a strategy for rational design and development of atomically precise nanomaterials via ligand tailoring and alloy engineering for a reversible stimuli-response behavior required for intelligent devices. The two temperature-driven, mutually convertible isomers of the nanoclusters open up an avenue to employ ultra-small nanoclusters (1 nm) for the design of thermal sensors and intelligent catalysts.

Novel Tri-Cholesteryl Derivatives-Based Low Molecular Mass Organic Gelators with Multi-Stimuli Responsive Properties

2015 ◽  
Vol 68 (5) ◽  
pp. 836
Author(s):  
Min Xue ◽  
Chunmeng Yu ◽  
Gang Wang ◽  
Hang Yu ◽  
Yu Fang
Keyword(s):  
Electron Microscopy ◽  
Molecular Mass ◽  
Driving Force ◽  
Sol Gel ◽  
Stimuli Responsive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hcl Gas ◽  
Gel Phase ◽  
Scanning Electron

Two novel tri-cholesteryl derivatives 1 and 2 have been designed and prepared. Gelation tests in 30 liquids revealed that 1 is a more efficient gelator than 2. Interestingly, the gel of 1/cyclohexane shows a reversible sol–gel phase transition in response to a variety of disparate stimuli such as temperature, stress, and HCl gas. In particular, a fully reversible thixotropic property was observed, which has been rarely reported before. Fourier transform infrared spectroscopy and 1H NMR measurements revealed that hydrogen bonding is an important driving force for the formation of the gel networks. The network structures of 1 and 2 in their cyclohexane gels were studied by scanning electron microscopy and X-ray diffraction analyses, and possible packing models were proposed accordingly. The findings demonstrated in the present work suggest that there is a big potential for developing tri-cholesteryl derivatives into extraordinary low molecular mass gelators.

Process Simulation Role in the Development of New Alloys Based on an Integrated Computational Materials Engineering Approach

2014 ◽  
Author(s):  
Adrian S. Sabau ◽  
Wallace D. Porter ◽  
Shibayan Roy ◽  
Amit Shyam
Keyword(s):  
National Laboratory ◽  
Metal Casting ◽  
New Materials ◽  
Materials Properties ◽  
Design And Optimization ◽  
Oak Ridge ◽  
Materials Engineering ◽  
Integrated Computational Materials Engineering ◽  
Computational Materials ◽  
Physical Phenomena

To accelerate the introduction of new materials and components, the development of metal casting processes requires the teaming between different disciplines, as multi-physical phenomena have to be considered simultaneously for the process design and optimization for mechanical properties. The required models for physical phenomena as well as their validation status for metal casting are reviewed. The data on materials properties, model validation, and relevant microstructure for materials properties are highlighted. One vehicle to accelerate the development of new materials is through combined experimental-computational efforts. Integrated computational/experimental practices are reviewed; strengths and weaknesses are identified with respect to metal casting processes. Specifically, the examples are given for the knowledge base established at Oak Ridge National Laboratory and computer models for predicting casting defects and microstructure distribution in aluminum alloy components.

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