Photo-control of the thermal radical recombination reaction: photochromism of an azobenzene-bridged imidazole dimer

2015 ◽  
Vol 87 (6) ◽  
pp. 511-523 ◽  
Author(s):  
Katsuya Mutoh ◽  
Hiroki Arai ◽  
Yoichi Kobayashi ◽  
Jiro Abe
Keyword(s):  
Recombination Reaction ◽  
Long Distance ◽  
Radical Pairs ◽  
Photochromic Compounds ◽  
Radical Recombination ◽  
Azobenzene Moiety ◽  
Potential Applications ◽  
New Type ◽  
Holographic Displays ◽  
Recombination Reactions

AbstractAmong various kinds of photochromic compounds, bridged imidazole dimers have been known as fast photo-switch molecules. Bridged imidazole dimers have opened up various potential applications to photochromic lenses and real-time holographic displays. The optical properties of bridged imidazole dimers strongly depend on the bridging moiety to tether two imidazole rings. Therefore, the control of the bridging structure by introducing another photochromic moiety would increase the versatility of bridged imidazole dimers. In this study, we designed and synthesized a new type of the bridged imidazole dimer 1 which has the azobenzene moiety as the photo-responsive linker. The cis–trans isomerization of the azobenzene moiety enables to change the distance between the photogenerated radical pairs. The two structural isomers, cis–1 and trans–1, are observed and both compounds undergo the photochromism to produce the imidazolyl radicals. We found that the two imidazolyl radicals generated from cis–1 are close enough to form the intramolecular C–N bond, whereas the imidazolyl radicals of trans–1 undergo the intermolecular recombination reaction due to the long distance between the radicals. Our results demonstrate the control of intra-/intermolecular radical recombination reactions by the combination of the two photochromic compounds.

scholarly journals Bio-inspired Fog Harvesting Materials: Basic Research and Bionic Potential Applications

2021 ◽  
Vol 18 (3) ◽  
pp. 501-533
Author(s):  
Kui Wan ◽  
Xuelian Gou ◽  
Zhiguang Guo
Keyword(s):  
Collection Efficiency ◽  
Basic Research ◽  
Development Trend ◽  
Water Mist ◽  
Long Distance ◽  
Biological Water ◽  
Water Collection ◽  
Transmission Area ◽  
Potential Applications ◽  
Water Transmission

AbstractWith the explosive growth of the world’s population and the rapid increase in industrial water consumption, the world’s water supply has fallen into crisis. The shortage of fresh water resources has become a global problem, especially in arid regions. In nature, many organisms can collect water from foggy water under harsh conditions, which provides us with inspiration for the development of new functional fog harvesting materials. A large number of bionic special wettable synthetic surfaces are synthesized for water mist collection. In this review, we introduce some water collection phenomena in nature, outline the basic theories of biological water harvesting, and summarize six mechanisms of biological water collection: increased surface wettability, increased water transmission area, long-distance water delivery, water accumulation and storage, condensation promotion, and gravity-driven. Then, the water collection mechanisms of three typical organisms and their synthesis are discussed. And their function, water collection efficiency, new developments in their biomimetic materials are narrated, which are cactus, spider and desert beetles. The study of multiple bionics was inspired by the discovery of Nepenthes’ moist and smooth peristome. The excellent characteristics of a variety of biological water collection structures, combined with each other, are far superior to other single synthetic surfaces. Furthermore, the main problems in the preparation and application of biomimetic fog harvesting materials and the future development trend of materials fog harvesting are prospected.

A New Type of Cuprous-Cysteamine Sensitizers: Synthesis, Optical Properties and Potential Applications

2021 ◽  
pp. 100435
Author(s):  
Yan Wang ◽  
Noura Dawas Alkhaldi ◽  
Nil Kanatha Pandey ◽  
Lalit Chudal ◽  
Lingyun Wang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Potential Applications ◽  
New Type

Effects of weak magnetic fields on free radical recombination reactions

1998 ◽  
Vol 95 (1) ◽  
pp. 71-89 ◽  
Author(s):  
C.R. Timmel ◽  
U. Till ◽  
B. Brocklehurst ◽  
K.A. Mclauchlan ◽  
P.J. Hore
Keyword(s):  
Free Radical ◽  
Magnetic Fields ◽  
Radical Recombination ◽  
Weak Magnetic Fields ◽  
Recombination Reactions

New Type of Hydraulic Rotary Actuator; Development and Application in a Large Telerobotic Manipulator System

2001 ◽  
Author(s):  
John R. Haas
Keyword(s):  
Modular Design ◽  
Large Diameter ◽  
Stick Slip ◽  
Precision Motion Control ◽  
Constant Torque ◽  
Rotary Actuator ◽  
Continuous Rotation ◽  
Potential Applications ◽  
New Type ◽  
Precision Motion

Abstract This paper describes a new type of hydraulic rotary actuator specifically developed to provide precision motion control in a very large, man rated, underwater telerobotic manipulator system. The high pressure, high torque rotary actuators are hydrostatically balanced, provide continuous rotation, constant torque output, exhibit minimal “stick-slip” and zero backlash. It is believed that the combination of features and the performance exhibited by these actuators represent an improvement in actuator technology to such an extent as to make projects previously determined unfeasible, now practical. Features of particular design value are a very large diameter through bore, and a truly modular design permitting use as an integral structural member. This paper will address design rationale, operating principles, key design features, product development highlights, an astronaut trainer case study, future development and potential applications.

A Novel, Low-Cost C-C Composite Heat Sink Material

1996 ◽  
Vol 445 ◽  
Author(s):  
W. Kowbel ◽  
V. Chellappa ◽  
J.C. Withers
Keyword(s):  
Thermal Conductivity ◽  
Heat Sink ◽  
Low Cost ◽  
Mechanical And Thermal Properties ◽  
New Class ◽  
Dielectric Coatings ◽  
Potential Applications ◽  
New Material ◽  
New Type ◽  
Composite Heat

AbstractRapid advances in high power electronics packaging require the development of new heat sink materials. Advanced composites designed to provide thermal expansion control as well as improved thermal conductivity have the potential to provide benefits in the removal of excess heat from electronic devices. Carbon-carbon (C-C) composits are under consideration for several military and space electronic applications including SEM-E electronic boxes. The high cost of C-C composits has greatly hindered their wide spread commercialization. A new manufacturing process has been developed to produce high thermal conductivity (over 400 W/mK) C-C composites at greatly reduced cost (less than $50/lb). This new material has potential applications as both a heat sink and a substrate. Dielectric coatings such as A1N and diamond were applied to this new type of heat sink material. Processing, as well as mechanical and thermal properties of this new class of heat sink material will be presented.

Spin catalysis of the radical recombination reaction

1995 ◽  
Vol 233 (3) ◽  
pp. 315-318 ◽  
Author(s):  
Anatoly L. Buchachenko ◽  
Lyudmila V. Ruban ◽  
Eugene N. Step ◽  
Nicholas J. Turro
Keyword(s):  
Recombination Reaction ◽  
Radical Recombination

scholarly journals A critical review on the development and performance of polymer/graphene nanocomposites

2018 ◽  
Vol 25 (6) ◽  
pp. 1059-1073 ◽  
Author(s):  
Weifeng Chen ◽  
Hu Weimin ◽  
Dejiang Li ◽  
Shaona Chen ◽  
Zhongxu Dai
Keyword(s):  
Polymer Nanocomposites ◽  
Electronic Conductivity ◽  
Future Research ◽  
Preparation Methods ◽  
Graphene Nanocomposites ◽  
Advantages And Disadvantages ◽  
Solution Blending ◽  
Potential Applications ◽  
New Type ◽  
And Performance

AbstractGraphene (graphene) is a new type of two-dimensional inorganic nanomaterial developed in recent years. It can be used as an ideal inorganic nanofiller for the preparation of polymer nanocomposites because of its high mechanical strength, excellent electrical conductivity and plentiful availability (from graphite). In this review, the preparation methods of graphene/polymer nanocomposites, including solution blending, melt blending and in situ polymerization, are introduced in order to study the relationship between these methods and the final characteristics and properties. Each method has an influence on the final characteristics and properties of the nanocomposites. The advantages and disadvantages of these methods are discussed. In addition, a variety of nanocomposites with different properties, such as mechanical properties, electronic conductivity, thermal conductivity and thermal properties, are summarized comprehensively. The potential applications of these nanocomposites in conductive materials, electromagnetic shielding materials, photocatalytic materials and so on, are briefly presented. This review demonstrates that polymer/graphene nanocomposites exhibit superior comprehensive performance and will be applied in the fields of new materials and novel devices. Future research directions of the nanocomposites are also presented.

scholarly journals Kinematic analysis and simulation of a new type of differential micro-feed mechanism with friction

2019 ◽  
Vol 103 (1) ◽  
pp. 003685041987566
Author(s):  
Hanwen Yu ◽  
Xianying Feng ◽  
Qun Sun
Keyword(s):  
Mechanical Efficiency ◽  
System Structure ◽  
Advanced Technology ◽  
Ball Screw ◽  
National Defense ◽  
Integrated Electronics ◽  
Contact Points ◽  
Feed Control ◽  
Potential Applications ◽  
New Type

This article presents a new micro-feed mechanism, whose main transmission component is the nut–rotary ball screw pair. The screw and nut are driven by two motors, and they rotate in the same direction, with their movements enabling micro-feeding. The main contribution of the micro-feed mechanism is to avoid the inevitable low-speed nonlinear creeping phenomenon caused by the inherent properties of traditional electromechanical servo system structure, thus realizing high precision micro-feed. In this study, the motion state of the working ball is analyzed using the principle of differential geometry, the friction at the contact points is calculated, the balance equation for force and moment is established, the influences of the screw and nut on the kinematic parameters of the ball at different velocities and the differences in the motion states of the ball in different drive modes are studied, and the mechanical efficiency of the dual-driven ball screw mechanism is calculated. The potential applications of the new micro-feed mechanism and the results of numerical analysis can be applied to advanced technology fields such as robotics, suspensions, powertrain, national defense, integrated electronics, optoelectronics, medicine, and genetic engineering, so that the new system can have a lower stable speed limit and achieve precise micro-feed control.

scholarly journals Highly Efficient Synthesis of Hindered 3-Azoindoles via Metal-Free C–H Functionalization of Indoles

Synthesis ◽  
2020 ◽  
Vol 52 (04) ◽  
pp. 574-580
Author(s):  
Nicolas Jacob ◽  
Lucas Guillemard ◽  
Joanna Wencel-Delord
Keyword(s):  
Steric Hindrance ◽  
Room Temperature ◽  
Efficient Synthesis ◽  
Atom Economy ◽  
Photochromic Compounds ◽  
Metal Free ◽  
Highly Efficient ◽  
Simple Protocol ◽  
Potential Applications

Although 3-azoindoles have recently emerged as an appealing family of photoswitch molecules, the synthesis of such compounds has been poorly covered in the literature. Herein a high-yielding and operationally simple protocol is reported allowing the synthesis of 3-azoindoles, featuring important steric hindrance around the azo motif. Remarkably, this C–H coupling is characterized by excellent atom economy and occurs under metal-free conditions, at room temperature, and within few minutes, delivering the expected products in excellent yields (quantitatively in most of the cases). Accordingly, a library of new molecules, with potential applications as photochromic compounds, is prepared.

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