A new approach to switchable photochromic materials by combining photochromism and piezochromism together in an AIE-active molecule

2017 ◽  
Vol 1 (9) ◽  
pp. 1900-1904 ◽  
Author(s):  
Tao Yu ◽  
Depei Ou ◽  
Leyu Wang ◽  
Shizhao Zheng ◽  
Zhiyong Yang ◽  
...  
Keyword(s):  
Active Molecule ◽  
New Approach ◽  
Photochromic Material ◽  
Photochromic Materials

Switchable photochromic material was achieved by combining photochromism and piezochromism together. The photochromic ON/OFF states can be easily controlled and indicated.

Photochromism of Neutral Spiropyran in the Crystalline State at Room Temperature

2021 ◽  
Author(s):  
Zhen Wu ◽  
Qian Wang ◽  
Pengyu Li ◽  
Bing Fang ◽  
Meizhen Yin
Keyword(s):  
Optical Properties ◽  
Solid State ◽  
Crystalline State ◽  
Room Temperature ◽  
Functional Materials ◽  
Photochromic Material ◽  
Tunable Optical Properties ◽  
Photochromic Materials

Solid-state photochromic materials are very attractive due to their promising future in advanced functional materials with reversible and tunable optical properties. However, the development of photochromic material in the solid...

scholarly journals A New Approach for Studying Bond Rupture/Closure of a Spiro Benzopyran Photochromic Material: Reactivity Descriptors Derived from Frontier Orbitals and DFT Computed Electrostatic Potential Energy Surface Maps

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
M. S. A. Abdel-Mottaleb ◽  
Sarah N. Ali
Keyword(s):  
Potential Energy ◽  
Electrostatic Potential ◽  
Potential Energy Surfaces ◽  
Bond Rupture ◽  
Photochromic Properties ◽  
Reactivity Descriptors ◽  
Photochromic Material ◽  
Td Dft ◽  
Photochromic Materials ◽  
Electrostatic Potential Energy

This paper focuses on computations technique within the framework of the TD-DFT theory for studying the relationship between structure-properties of reversible conversion of photochromic materials. Specifically, we report on 1′,3′-dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2′-(2H)-indole] (SP) and its isomers. TD-DFT calculated UV-Vis electronic spectra of the closed and open isomers of this photochromic material are in excellent agreement with the experimental results. Moreover, this paper reports on the results of theoretical investigations of reactivity indices that may govern the conversion between spiropyrans and its isomers. In addition, the solvent and rigidity of the medium significantly control the thermal bleaching of the photogenerated colored isomers and hence the switch ability pattern of the photochromic material. The effect of molecular structure computed by DFT in gas-phase and solvents onCspiro-Obond length has been shown to correlate with photochromic properties. For this compound, DFT optimized geometry could be used to predict photochromism. Furthermore, in an attempt to predict the driving force for MC → SP, this work explores, for the first time, profitable exploitation of the calculated and visualized mapped electrostatic potential energy surfaces (ESP map). Interestingly, it seems that the electrostatic potential forces over the molecular fragments govern spirobond rupture/closure reactions. Thermodynamically, all-trans-colored isomer (CTT) is the most stable merocyanine-like form.

scholarly journals Cooperative and Fully Reversible Photocatalytic Colour Switching Activation in Graphene-Copper-TiO2 Nanoparticles

2020 ◽  
Author(s):  
David Maria Tobaldi ◽  
Luc Lajaunie ◽  
Dana Dvoranova ◽  
Bruno Figueiredo ◽  
Maria Paula Seabra ◽  
...  
Keyword(s):  
Visible Light ◽  
Optical Sensors ◽  
Uv Light ◽  
Synthesis Methods ◽  
High Electron ◽  
Smart Windows ◽  
Photochromic Material ◽  
Nanostructured Systems ◽  
Excellent Candidate ◽  
Photochromic Materials

<p>Nanostructured systems showing reversible colour switching are envisaged to play a significant role in photo-switches, photo-optical sensors, smart windows, displays, optical storage memories. Most of the materials exhibiting reversible colour switching are organic compounds. However, their UV-light activation, low thermal and chemical stability, as well as harmful synthesis methods, are of limit for their extensive use. In this research, we have created an inorganic switchable photochromic material exploiting: (i) TiO<sub>2</sub> ability of creating an exciton upon excitation, (ii) copper as the chromophore, and (iii) graphene’s extraordinarily high electron mobility. Our material showed itself to be able to work under visible-light, its photochromic property being three times faster than conventional titania based photochromic materials, reaching a stable change in colouration after only 30 mins of visible-light irradiation (<i>versus</i> > 120 min in conventional Cu-TiO<sub>2</sub>). With the addition of just 1 wt% graphene, the material exhibited a staggeringly stable photochromic switching over repeated cycles. These results relate to the best previously reported values for any form of TiO<sub>2</sub>-based photochromic material. This is therefore an excellent candidate for smart self-cleaning windows, and other chromic devices and applications.</p>

scholarly journals Cooperative and Fully Reversible Photocatalytic Colour Switching Activation in Graphene-Copper-TiO2 Nanoparticles

2020 ◽  
Author(s):  
David Maria Tobaldi ◽  
Luc Lajaunie ◽  
Dana Dvoranova ◽  
Bruno Figueiredo ◽  
Maria Paula Seabra ◽  
...  
Keyword(s):  
Visible Light ◽  
Optical Sensors ◽  
Uv Light ◽  
Synthesis Methods ◽  
High Electron ◽  
Smart Windows ◽  
Photochromic Material ◽  
Nanostructured Systems ◽  
Excellent Candidate ◽  
Photochromic Materials

<p>Nanostructured systems showing reversible colour switching are envisaged to play a significant role in photo-switches, photo-optical sensors, smart windows, displays, optical storage memories. Most of the materials exhibiting reversible colour switching are organic compounds. However, their UV-light activation, low thermal and chemical stability, as well as harmful synthesis methods, are of limit for their extensive use. In this research, we have created an inorganic switchable photochromic material exploiting: (i) TiO<sub>2</sub> ability of creating an exciton upon excitation, (ii) copper as the chromophore, and (iii) graphene’s extraordinarily high electron mobility. Our material showed itself to be able to work under visible-light, its photochromic property being three times faster than conventional titania based photochromic materials, reaching a stable change in colouration after only 30 mins of visible-light irradiation (<i>versus</i> > 120 min in conventional Cu-TiO<sub>2</sub>). With the addition of just 1 wt% graphene, the material exhibited a staggeringly stable photochromic switching over repeated cycles. These results relate to the best previously reported values for any form of TiO<sub>2</sub>-based photochromic material. This is therefore an excellent candidate for smart self-cleaning windows, and other chromic devices and applications.</p>

The O–C diagrams of minor planets − a new approach to modelling the rotation

1999 ◽  
Vol 173 ◽  
pp. 185-188
Author(s):  
Gy. Szabó ◽  
K. Sárneczky ◽  
L.L. Kiss
Keyword(s):  
Error Analysis ◽  
Time Dependence ◽  
Theoretical Work ◽  
Minor Planet ◽  
Minor Planets ◽  
New Approach ◽  
Preliminary Results ◽  
Ccd Observations

AbstractA widely used tool in studying quasi-monoperiodic processes is the O–C diagram. This paper deals with the application of this diagram in minor planet studies. The main difference between our approach and the classical O–C diagram is that we transform the epoch (=time) dependence into the geocentric longitude domain. We outline a rotation modelling using this modified O–C and illustrate the abilities with detailed error analysis. The primary assumption, that the monotonity and the shape of this diagram is (almost) independent of the geometry of the asteroids is discussed and tested. The monotonity enables an unambiguous distinction between the prograde and retrograde rotation, thus the four-fold (or in some cases the two-fold) ambiguities can be avoided. This turned out to be the main advantage of the O–C examination. As an extension to the theoretical work, we present some preliminary results on 1727 Mette based on new CCD observations.

A New Approach to the Demonstration of Oxidase-Localization Using Tannic Acid Or Catechin

1973 ◽  
Vol 31 ◽  
pp. 698-699
Author(s):  
V. Mizuhira ◽  
Y. Futaesaku
Keyword(s):  
Cross Section ◽  
Tannic Acid ◽  
Elastic Fiber ◽  
The Other ◽  
New Approach ◽  
Tissue Block ◽  
Active Reaction ◽  
The Cross

Previously we reported that tannic acid is a very effective fixative for proteins including polypeptides. Especially, in the cross section of microtubules, thirteen submits in A-tubule and eleven in B-tubule could be observed very clearly. An elastic fiber could be demonstrated very clearly, as an electron opaque, homogeneous fiber. However, tannic acid did not penetrate into the deep portion of the tissue-block. So we tried Catechin. This shows almost the same chemical natures as that of proteins, as tannic acid. Moreover, we thought that catechin should have two active-reaction sites, one is phenol,and the other is catechole. Catechole site should react with osmium, to make Os- black. Phenol-site should react with peroxidase existing perhydroxide.

Processing Immunoperoxidase Labeled Cell Monolayers and Cryostat Sesctions For Electron Microscopy

1985 ◽  
Vol 43 ◽  
pp. 714-715
Author(s):  
K. Chien ◽  
R. Van de Velde ◽  
I.P. Shintaku ◽  
A.F. Sassoon
Keyword(s):  
Cell Monolayer ◽  
Cell Types ◽  
Surface Antigens ◽  
Immunoperoxidase Method ◽  
Reaction Step ◽  
Hot Plate ◽  
Air Drying ◽  
New Approach ◽  
Cell Monolayers ◽  
Glass Slides

Immunoelectron microscopy of neoplastic lymphoma cells is valuable for precise localization of surface antigens and identification of cell types. We have developed a new approach in which the immunohistochemical staining can be evaluated prior to embedding for EM and desired area subsequently selected for ultrathin sectioning.A freshly prepared lymphoma cell suspension is spun onto polylysine hydrobromide- coated glass slides by cytocentrifugation and immediately fixed without air drying in polylysine paraformaldehyde (PLP) fixative. After rinsing in PBS, slides are stained by a 3-step immunoperoxidase method. Cell monolayer is then fixed in buffered 3% glutaraldehyde prior to DAB reaction. After the DAB reaction step, wet monolayers can be examined under LM for presence of brown reaction product and selected monolayers then processed by routine methods for EM and embedded with the Chien Re-embedding Mold. After the polymerization, the epoxy blocks are easily separated from the glass slides by heatingon a 100°C hot plate for 20 seconds.

TEM study of a biofilm on copper corrosion

1996 ◽  
Vol 54 ◽  
pp. 220-221
Author(s):  
W. A. Chiou ◽  
N. Kohyama ◽  
B. Little ◽  
P. Wagner ◽  
M. Meshii
Keyword(s):  
Marine Bacterium ◽  
Culture Medium ◽  
Copper Alloys ◽  
Pure Copper ◽  
Localized Corrosion ◽  
Natural Seawater ◽  
Copper Corrosion ◽  
New Approach ◽  
The Past ◽  
Copper Tolerant

The corrosion of copper and copper alloys in a marine environment is of great concern because of their widespread use in heat exchangers and steam condensers in which natural seawater is the coolant. It has become increasingly evident that microorganisms play an important role in the corrosion of a number of metals and alloys under a variety of environments. For the past 15 years the use of SEM has proven to be useful in studying biofilms and spatial relationships between bacteria and localized corrosion of metals. Little information, however, has been obtained using TEM capitalizing on its higher spacial resolution and the transmission observation of interfaces. The research presented herein is the first step of this new approach in studying the corrosion with biological influence in pure copper.Commercially produced copper (Cu, 99%) foils of approximately 120 μm thick exposed to a copper-tolerant marine bacterium, Oceanospirillum, and an abiotic culture medium were subsampled (1 cm × 1 cm) for this study along with unexposed control samples.

High resolution at low voltage: A new approach

1989 ◽  
Vol 47 ◽  
pp. 76-77
Author(s):  
Arthur V. Jones
Keyword(s):  
Low Voltage ◽  
Emission Sources ◽  
New Approach ◽  
Design Concepts ◽  
Probe Diameter ◽  
Low Voltage Operation ◽  
Sufficient Intensity ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Immersion Type

With the introduction of field-emission sources and “immersion-type” objective lenses, the resolution obtainable with modern scanning electron microscopes is approaching that obtainable in STEM and TEM-but only with specific types of specimens. Bulk specimens still suffer from the restrictions imposed by internal scattering and the need to be conducting. Advances in coating techniques have largely overcome these problems but for a sizeable body of specimens, the restrictions imposed by coating are unacceptable.For such specimens, low voltage operation, with its low beam penetration and freedom from charging artifacts, is the method of choice.Unfortunately the technical dificulties in producing an electron beam sufficiently small and of sufficient intensity are considerably greater at low beam energies — so much so that a radical reevaluation of convential design concepts is needed.The probe diameter is usually given by

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