Quantitative end-group functionalization of PNIPAM from aqueous SET-LRP via in situ reduction of Cu(ii) with NaBH4

2016 ◽  
Vol 7 (29) ◽  
pp. 4802-4809 ◽  
Author(s):  
Mikhail Gavrilov ◽  
Zhongfan Jia ◽  
Virgil Percec ◽  
Michael J. Monteiro
Keyword(s):  
Click Reaction ◽  
In Situ Reduction ◽  
End Group Functionalization ◽  
Very High ◽  
End Group

Rapid in situ azidation and CuAAC ‘click’ reaction demonstrating very high chain-end functionality.

Synthesis and Characterization of Poly(2-acrylamido-2-methyl propyl sulfonic acid-co-2-hydroxyethyl methclate)/ Silver Nanoparticle Composite Hydrogel as Catalysts for the Reduction of 4-Nitrophenol

2014 ◽  
Vol 809-810 ◽  
pp. 59-66
Author(s):  
Yun Long Li ◽  
Bin Huang Liu ◽  
Song Bai Lin
Keyword(s):  
Sulfonic Acid ◽  
Reduction Method ◽  
Catalytic Properties ◽  
Reduction Reaction ◽  
Composite Hydrogel ◽  
Synthesis And Characterization ◽  
In Situ Reduction ◽  
End Group

A novel kind of AgNPs catalyst was synthesized by in-situ reduction method using poly(2-acrylamido-2-methyl propyl sulfonic acid-co-2-hydroxyethyl methclate) [short as P(AMPS-co-HEMA)] hydrogel as matrices and AgNO3as a metal precursor. The structure of the composite hydrogel was characterized by Scan Electrical Microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The results showed that AgNPs were binded with end group and most of the particles were isolated and uniformly distributed on the P(AMPS-co-HEMA). The catalytic properties in the reduction reaction of 4-nitrophenol(shorted as 4-NP) to 4-aminophenol(shorted as 4-AP) were studied in detail, and the result showed that conversion rate and conversion efficiency attained 97.56% and 0.9671 mmol/g·min when the amount of AgNPs was 9mg, [NaBH4] was 2.0×10−1mol/L, [4-NP] was 2.0×10−2mol/L and the total volume of solution was 50 mL, respectively.

Dehydrocyclization of Diphenylamine to Carbazole Over Platinum Catalysts

2008 ◽  
Vol 73 (8-9) ◽  
pp. 1149-1160 ◽  
Author(s):  
Miroslav Vlčko ◽  
Zuzana Cvengrošová ◽  
Milan Hronec
Keyword(s):  
Citric Acid ◽  
Gas Phase ◽  
Platinum Catalysts ◽  
Pt Catalyst ◽  
Pt Catalysts ◽  
In Situ Reduction ◽  
Wet Impregnation ◽  
Very High

The gas-phase dehydrocyclization of diphenylamine (DPA) to carbazole over alumina-supported 0.4 wt.% Pt catalysts in a fix-bed reactor has been studied. The reaction was carried out at a temperature of 550 °C in the presence of hydrogen. All catalysts became well dispersed Pt after in situ reduction. Pt catalysts prepared in the presence of a competitive adsorbate (citric acid) were reasonably active during first hours on stream (DPA conversion higher than 90%). However, later, their activity decreased rapidly, except the catalyst prepared in the presence of a higher concentration of the competitive agent. The same trend was observed for the Pt catalyst prepared by wet impregnation. The activity of the catalysts prepared by a microemulsion technique was very high and stable during testing, the conversion of DPA being higher than 93%. However, the selectivities of catalysts prepared in the presence of citric acid gradually decreased with time on stream (TOS). The initial selectivityof such prepared catalysts for carbazole was about 60%. The same trend was observed for catalysts prepared by microemulsion technique. The highest selectivities, 73%, were obtained over the catalysts prepared by wet impregnation; it dropped after 6 days of testing to about 62%.

scholarly journals Facile discovery of isonitrile natural products via tetrazine based click reactions

2019 ◽  
Author(s):  
Yaobing Huang ◽  
Wenlong Cai ◽  
Antonio Del Rio Flores ◽  
Frederick Twigg ◽  
Wenjun Zhang
Keyword(s):  
Natural Products ◽  
Click Reaction ◽  
In Situ Reduction ◽  
Click Reactions ◽  
Microbial Cultures ◽  
First Time

A facile method for the quick discovery and quantification of isonitrile compounds from microbial cultures was established based on the isonitrile-tetrazine click reaction. A in situ reduction further enabled bioorthogonal ligation of primary and secondary isonitriles for the first time.

scholarly journals Critical Dynamics of Defects and Mechanisms of Damage-Failure Transitions in Fatigue

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2554
Author(s):  
Oleg Naimark ◽  
Vladimir Oborin ◽  
Mikhail Bannikov ◽  
Dmitry Ledon
Keyword(s):  
Fatigue Damage ◽  
Kinetic Equations ◽  
Experimental Methodology ◽  
Preliminary Deformation ◽  
Scaling Properties ◽  
In Situ Data ◽  
Number Of Cycles ◽  
Fish Eye ◽  
Very High

An experimental methodology was developed for estimating a very high cycle fatigue (VHCF) life of the aluminum alloy AMG-6 subjected to preliminary deformation. The analysis of fatigue damage staging is based on the measurement of elastic modulus decrement according to “in situ” data of nonlinear dynamics of free-end specimen vibrations at the VHCF test. The correlation of fatigue damage staging and fracture surface morphology was studied to establish the scaling properties and kinetic equations for damage localization, “fish-eye” nucleation, and transition to the Paris crack kinetics. These equations, based on empirical parameters related to the structure of the material, allows us to estimate the number of cycles for the nucleation and advance of fatigue crack.

scholarly journals Thermally-induced hyperbranching of bromine-containing polyesters by insertion of in situ generated chain-end carbenes

2021 ◽  
Author(s):  
Panos Bexis ◽  
Craig Bell ◽  
Maria Chiara Arno ◽  
Anthony Thomas ◽  
Andrew P Dove
Keyword(s):  
Thermally Induced ◽  
End Group

Hyperbranched, biodegradable PCL-based polymers are obtained through a random but invasive migration of an in-situ generated carbene end group which is unmasked via the thermolysis of its precursor diazirine moiety....

scholarly journals A Pixel Design of a Branching Ultra-Highspeed Image Sensor

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2506
Author(s):  
Nguyen Hoai Ngo ◽  
Kazuhiro Shimonomura ◽  
Taeko Ando ◽  
Takayoshi Shimura ◽  
Heiji Watanabe ◽  
...  
Keyword(s):  
Image Sensor ◽  
Frame Rate ◽  
Front Side ◽  
Digital Signals ◽  
Memory Element ◽  
Image Capture ◽  
Readout Circuits ◽  
Pros And Cons ◽  
Very High

A burst image sensor named Hanabi, meaning fireworks in Japanese, includes a branching CCD and multiple CMOS readout circuits. The sensor is backside-illuminated with a light/charge guide pipe to minimize the temporal resolution by suppressing the horizontal motion of signal carriers. On the front side, the pixel has a guide gate at the center, branching to six first-branching gates, each bifurcating to second-branching gates, and finally connected to 12 (=6×2) floating diffusions. The signals are either read out after an image capture operation to replay 12 to 48 consecutive images, or continuously transferred to a memory chip stacked on the front side of the sensor chip and converted to digital signals. A CCD burst image sensor enables a noiseless signal transfer from a photodiode to the in-situ storage even at very high frame rates. However, the pixel count conflicts with the frame count due to the large pixel size for the relatively large in-pixel CCD memory elements. A CMOS burst image sensor can use small trench-type capacitors for memory elements, instead of CCD channels. However, the transfer noise from a floating diffusion to the memory element increases in proportion to the square root of the frame rate. The Hanabi chip overcomes the compromise between these pros and cons.

Catalytic dehydrogenation of amines to imines and the in-situ reduction of sulfoxides into sulfides

2021 ◽  
Author(s):  
Xixi Liu ◽  
Yanxin Wang ◽  
Bo Li ◽  
Bing Liu ◽  
Wei Wang ◽  
...  
Keyword(s):  
Catalytic Dehydrogenation ◽  
In Situ Reduction

Physicochemical properties of geopolymer composites with DFT calculations of in-situ reduction of graphene oxide

2021 ◽  
Author(s):  
Amun Amri ◽  
Ahmad Ainun Najib ◽  
Monita Olivia ◽  
Mohammednoor Altarawneh ◽  
Aman Syam ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Dft Calculations ◽  
Physicochemical Properties ◽  
In Situ Reduction ◽  
Geopolymer Composites

scholarly journals Influence of Hydrogeochemistry on Tunnel Drainage in Evaporitic Formations: El Regajal Tunnel Case Study (Aranjuez, Spain)

2021 ◽  
Vol 13 (3) ◽  
pp. 1505
Author(s):  
Ignacio Menéndez Pidal ◽  
Jose Antonio Mancebo Piqueras ◽  
Eugenio Sanz Pérez ◽  
Clemente Sáenz Sanz
Keyword(s):  
High Speed ◽  
Civil Engineering ◽  
Saturation Index ◽  
The Subject ◽  
Under Construction ◽  
Underground Flow ◽  
Very High ◽  
Over Time

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.

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