Recent Synthetic Advances on π-Extended Carbon Nanohoops

Synlett ◽  
2017 ◽  
Vol 28 (12) ◽  
pp. 1383-1388 ◽  
Author(s):  
Huan Cong ◽  
Yi Luan
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Synthesis ◽  
Rapid Progress ◽  
Ring Closing Metathesis ◽  
Bottom Up ◽  
Reaction Method ◽  
The Past

As a part of the ‘bottom-up’ campaign for the precise preparation of carbon nanotubes, the chemical synthesis of carbon nanohoops is observing rapid progress, with a number of milestone achievements, over the past decade. With simple carbon nanohoops (e.g. cycloparaphenylenes) now no longer elusive targets, this Synpacts article highlights latest synthetic advances to further build up nanohoops’ π-systems. Works reviewed herein include the study explaining the unsuccessful Scholl reaction method, the preparation of a carbon nanohoop consisting solely of hexabenzocoronene units, syntheses of π-extended carbon nanohoops employing the ring-closing metathesis method, and the anthracene photodimerization/cycloreversion method for anthracene-incorporated carbon nanohoop synthesis.1 Introduction2 Some Latest Syntheses of π-Extended Carbon Nanohoops3 Conclusion

“Forward to David the Builder!” Georgia's (re)turn to language-centered nationalism

2016 ◽  
Vol 44 (4) ◽  
pp. 522-542 ◽  
Author(s):  
Christofer Berglund
Keyword(s):  
Large Scale ◽  
Nation Building ◽  
The State ◽  
Top Down ◽  
Bottom Up ◽  
The Past ◽  
Building Project ◽  
The Rose ◽  
State Language

After the Rose Revolution, President Saakashvili tried to move away from the exclusionary nationalism of the past, which had poisoned relations between Georgians and their Armenian and Azerbaijani compatriots. His government instead sought to foster an inclusionary nationalism, wherein belonging was contingent upon speaking the state language and all Georgian speakers, irrespective of origin, were to be equals. This article examines this nation-building project from a top-down and bottom-up lens. I first argue that state officials took rigorous steps to signal that Georgian-speaking minorities were part of the national fabric, but failed to abolish religious and historical barriers to their inclusion. I next utilize a large-scale, matched-guise experiment (n= 792) to explore if adolescent Georgians ostracize Georgian-speaking minorities or embrace them as their peers. I find that the upcoming generation of Georgians harbor attitudes in line with Saakashvili's language-centered nationalism, and that current Georgian nationalism therefore is more inclusionary than previous research, or Georgia's tumultuous past, would lead us to believe.

scholarly journals The New Keynesian Synthesis

1993 ◽  
Vol 7 (1) ◽  
pp. 5-22 ◽  
Author(s):  
David Romer
Keyword(s):  
Current Understanding ◽  
New Keynesian ◽  
Price Rigidity ◽  
Rapid Progress ◽  
The Past ◽  
Nominal Rigidity

The new Keynesians made more rapid progress in understanding the microeconomics of unemployment than in understanding the microeconomics of nominal price rigidity. But the past five years have seen important breakthroughs in this second area. This paper will describe these breakthroughs, discuss our current understanding of nominal rigidity, and assess the work that remains to be done.

Large-Scale Patterning and Assembly of Carbon Nanotubes by Microfluidic Hydrodynamic Focusing

2011 ◽  
Vol 194-196 ◽  
pp. 503-506 ◽  
Author(s):  
Mei Liu ◽  
Yan Peng ◽  
Qiu Quan Guo ◽  
Jun Luo ◽  
Jun Yang
Keyword(s):  
Carbon Nanotubes ◽  
Mass Production ◽  
Large Scale ◽  
Sample Solution ◽  
Hydrodynamic Focusing ◽  
Bottom Up ◽  
General Pathway ◽  
Efficient Integration

Efficient integration of synthetic nanotubes/nanowires into functional nanodevices by bottom-up approaches is the key of mass production of nanodevices, and is still a big challenge. Here we present a simple microfluidic method of patterning and aligning a large scale of carbon nanotubes by hydrodynamic focusing: the sample solution carrying carbon nanotubes were hydrodynamically controlled by the sheath flows. This method can be used to align and position both a large scale of nanotubes and a few lines of nanotubes to designated positions, offering a general pathway for assembly of nanosystems.

Preparation and Property of Lanthanum Ferrite Formaldehyde Gas Sensor Modified by Carbon Nanotubes and Silver

2013 ◽  
Vol 320 ◽  
pp. 554-557 ◽  
Author(s):  
Yu Min Zhang ◽  
Yu Tao Lin ◽  
Jin Zhang ◽  
Zhong Qi Zhu ◽  
Qiang Liu ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Synthesis ◽  
Recovery Time ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Sol Gel ◽  
Lanthanum Ferrite ◽  
Gas Sensing Properties ◽  
Response And Recovery ◽  
Sensitive Property

Our previous study revealed that the gas sensitive property of Silver-modified Lanthanum Ferrite (Ag-LaFeO3) is well, but the operating temperature is still high and the sensitivity also needs to be improved. This work based on our previous study. Ag-LaFeO3 was further modified by the Carbon nanoTubes (CNTs). The Ag-LaFeO3 powder modified with CNTs (CNTs-Ag-LaFeO3) was prepared by a sol-gel method combined with microwave chemical synthesis. The structure and gas-sensing properties were investigated. The results show that the structure of CNTs-Ag-LaFeO3 is of orthogonal perovskite. The sensitivity of 0.75% CNTs-Ag-LaFeO3 powder for 1 ppm formaldehyde is 13 at 86°C. The response and recovery time are 100s and 60s, respectively. Moreover, the sensor also has an obvious response for 1ppm formaldehyde at 58°C.

Active-Passive Damping Characteristics of Extension and Shear Mode Piezoelectric Fiber Nano-Reinforced Composite (PFNRC)

2017 ◽  
Author(s):  
Kepin Kavathia ◽  
Manoj Settipalli ◽  
Samikkannu Raja
Keyword(s):  
Carbon Nanotubes ◽  
Epoxy Matrix ◽  
Effective Properties ◽  
Past Research ◽  
Piezoelectric Composite ◽  
Passive Damping ◽  
The Past ◽  
Reinforced Composite ◽  
Walled Carbon Nanotubes ◽  
Piezoelectric Fiber

This paper presents a simulation-based study to investigate the damping properties of a novel piezocomposite, consisting of piezoelectric fiber and epoxy reinforced with randomly orientated double walled carbon nanotubes (DWCNT), termed as piezoelectric fiber nano reinforced composite (PFNRC). Authors have observed that the past research dealt with the effect of aligned single walled carbon nanotubes (CNT) on active damping of piezoelectric composite in extension mode (e13 and e33). It is known from the past research that DWCNT inclusions improve the passive damping of a composite. Therefore, the authors use DWCNT inclusions to study the active-passive damping of the piezoelectric composite, in this article. The random orientation of the DWCNT is considered to replicate the physical composite as it known that aligning CNTs in a single direction is not feasible due to fabrication constraints. A multistep homogenization method involving Method of Cells (MOC) is employed to obtain effective properties of PFNRC. A modified 3D-MOC is used to obtain the effective properties of epoxy matrix with DWCNT inclusions (DWCNT-epoxy), considering the effect of nano particle agglomeration. A 2D-MOC is then implemented with long fiber PZT as the active material and DWCNT-epoxy as the matrix. This procedure is followed for computing the effective material properties of extension (e33) as well as shear (e15) mode of PFNRC, when DWCNT inclusions are added into the epoxy matrix at different weight percentages. The constitutive equations are derived with the help of Maple and simulated in MATLAB. These results are used to compare the active-passive damping performance of the composites using a single degree of freedom damping model, employing Newmark’s numerical integration method. The active damping performance of the composites is evaluated by varying the displacement and velocity gains in a negative feedback system. The main focus of the study is to find the most efficient operating mode of the proposed composite for damping of structural vibrations.

Plasma-Chemical Synthesis of Nanosized Powders-Nitrides, Carbides, Oxides, Carbon Nanotubes and Fullerenes

2012 ◽  
Vol 14 (11) ◽  
pp. 980-995 ◽  
Author(s):  
Katerina Zaharieva ◽  
Gheorghi Vissokov ◽  
Janis Grabis ◽  
Slavcho Rakovsky
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Synthesis ◽  
Plasma Chemical ◽  
Nanosized Powders ◽  
Plasma Chemical Synthesis
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