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Ben Zhong Tang - One of the best experts on this subject based on the ideXlab platform.
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metal free poly cycloaddition of activated azide and alkynes toward multifunctional polytriazoles aggregation induced emission explosive detection fluorescent patterning and Light Refraction
Macromolecular Rapid Communications, 2017Co-Authors: Changyun Quan, Ben Zhong Tang, Anjun Qin, Chao Zheng, Haiqin Deng, Zujin Zhao, Fei HuangAbstract:The metal-free click polymerization (MFCP) of activated alkynes and azides or activated azide and alkynes have been developed into powerful techniques for the construction of polytriazoles without the obsession of metallic catalyst residues problem. However, the MFCP of activated azides and alkynes is rarely applied in preparation of functional polytriazoles. In this paper, soluble multifunctional polytriazoles (PIa and PIb) with high weight-average molecular weights (Mw up to 32 000) are prepared via the developed metal-free poly-cycloaddition of activated azide and alkynes in high yields (up to 90%). The resultant PIa and PIb are thermally stable, and show aggregation-induced emission characteristics, enabling their aggregates to detect explosives with superamplification effect. Moreover, thanks to their containing aromatic rings and polar moieties, PIa and PIb exhibit high refractive indices. In addition, they can also be cross-linked upon UV irradiation to generate 2D fluorescent patterning due to their remaining azide groups and containing ester groups. Thus, these multifunctional polytriazoles are potentially applicable in the optoelectronic and sensing fields.
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thiol bromo click polymerization for multifunctional polymers synthesis Light Refraction aggregation induced emission and explosive detection
Polymer Chemistry, 2015Co-Authors: Yiren Zhang, Cathy Ka Wai Jim, Gan Chen, Yiliu Lin, Lifang Zhao, Wang Zhang Yuan, Yongming Zhang, Ben Zhong TangAbstract:New multifunctional polymers PI and PII are synthesized from 4,4′-thiodibenzenethiol and 1,2-bis[4-(bromoalkoxy)phenyl]-1,2-diphenylethene through facile thiol–bromo click polymerization. The resulting polymers exhibit high refractive indices over a wide spectral region (300–1700 nm) and large Abbe numbers due to the presence of sulfur atoms and a large fraction of aromatic building blocks. The polymers also show high optical transparency in the visible region, rendering them ideal candidates for optical applications. Additionally, they demonstrate typical aggregation-induced emission (AIE) characteristics owing to the incorporation of propeller-like tetraphenylethene (TPE) moieties. The polymers are nonemissive in good solvents; however, they become highly fluorescent as aggregated suspensions whose emission is further effectively quenched by a representative explosive of picric acid (PA), exhibiting a significantly amplified superquenching effect, with the detection limit as low as 0.5 ppm. These results suggest a great promise of preparing multifunctional polymers by thiol–bromo click polymerization with a rational molecular design.
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hyperbranched poly aroxycarbonyltriazole s metal free click polymerization Light Refraction aggregation induced emission explosive detection and fluorescent patterning
Macromolecules, 2013Co-Authors: Engui Zhao, Anjun Qin, Jing Zhi Sun, Ben Zhong TangAbstract:The metal-free click polymerization (MFCP) of azide and alkyne has become a powerful tool for the synthesis of functional polytriazoles. Among which, the MFCP of propiolate and azide has been used to prepare functional linear poly(aroxycarbonyltriazole)s (PACTs). Their hyperbranched analogues, however, have been rarely prepared. In this paper, hyperbranched PACTs with satisfactory molecular weights and high regioregularities were synthesized in high yields by the MFCP of tripropiolates (1) and tetraphenylethene (TPE)-containing diazide (2) under the optimized reaction conditions without protection from oxygen and moisture. The resultant polymers are soluble in common organic solvents and thermally stable, with 5% loss of their weights at temperatures higher than 330 °C. The polymers exhibit high refractive indices with low chromatic dispersion. Thanks to their contained TPE units, the polymers show the unique feature of aggregation-induced emission, and their aggregates can function as fluorescent sensors...
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ferrocene decorated hyperbranched poly aroxycarbonylphenylene s synthesis Light Refraction photopatterning and precursor to magnetic ceramics
Journal of Inorganic and Organometallic Polymers and Materials, 2013Co-Authors: Cathy Ka Wai Jim, Jacky Wing Yip Lam, Anjun Qin, Chris Wai Tung Leung, Liu Jianzhao, Herman H Y Sung, Ian D Williams, Ben Zhong TangAbstract:Ferrocene-decorated hyperbranched poly[1,3,5-tri(aroycarbonyl)phenylene]s (hb-PTACPs) are prepared in moderate yields with high molecular weights by one-pot polycyclotrimerization of 4,4′-isopropylidenediphenyl bipropiolate with 4-(ferrocenylmethyl)phenyl propiolate in reflux dimethylformamide. All the polymers are soluble and film-forming. They enjoy high thermal stability and lost little of their weight when heated to 300 °C under nitrogen. Thin solid films of the organometallic polymers shows high refractive indices (RI = 1.7038–1.6295) in the wavelength region of 400–1,700 nm. Ceramization of the organometallic hb-PTACPs at high temperature under inert atmosphere gives iron nanoparticles with high magnetizabilities. The organometallic polymers are readily crosslinked under UV irradiation and pyrolysis of the patterned polymer films produces magnetic ceramic patterns with good shape retention.
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luminogenic materials constructed from tetraphenylethene building blocks synthesis aggregation induced emission two photon absorption Light Refraction and explosive detection
Journal of Materials Chemistry, 2012Co-Authors: Rongrong Hu, Ben Zhong Tang, Joseluis Maldonado, Mario Rodriguez, Chunmei Deng, Matthew Ming Fai Yuen, Gabriel RamosortizAbstract:Luminogenic molecules [(TPE)3 (1), TPE-C = C-TPE-C = C-TPE (2), and TPE-C≡C-TPE-C≡C-TPE (3)] and their polymers P1–P3 are constructed from tetraphenylethene (TPE) building blocks in high yields by Suzuki, Witting, and Sonogashira coupling reactions. All the compounds are soluble and enjoy high thermal stability, losing little of their weights when they are heated to 290–528 °C under nitrogen or 288–436 °C in air. Analyses by UV spectroscopy and cyclic voltammetry as well as theoretical calculations show that the conjugation of the luminophores is in the order of 2 > 3 > 1, P2 > P3 > P1, and P1–P3 > 1–3. All the molecules and polymers are weakly emissive in solutions. They, however, become strong emitters in the aggregate state with fluorescence quantum yields up to 90%. Both 1–3 and P1–P3 exhibit the feature of aggregation-enhanced two-photon excited fluorescence. Large two-photon absorption cross sections (up to ∼900 GM) are observed in the nanoaggregates of the polymers. Thin solid films of the polymers show high refractive indices (RI = 1.7649 − 1.6873) in a wide wavelength region of 400–1700 nm, high modified Abbe numbers (vD′ up to 3436), and low optical dispersions (D′ down to 2.9 × 10−4). The Light emissions of the polymers can be quenched exponentially by picric acid with large quenching constants, suggesting that they can be utilized as efficient chemosensors for explosive detection.
Peng Lv - One of the best experts on this subject based on the ideXlab platform.
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double Refraction and spin splitter in normal conductor hexagonal semiconductor junctions
Physical Review B, 2018Co-Authors: Peng LvAbstract:In analogy with Light Refraction at optical boundary, ballistic electrons also undergo Refraction when propagate across a semiconductor junction. Establishing a negative refractive index in conventional optical materials is difficult, but the realization of negative Refraction in electronic system is conceptually straightforward, which has been verified in graphene p-n junctions in recent experiments. Here, we propose a model to realize double Refraction and double focusing of electric current by a normal-hexagonal semiconductor junction. The double Refraction can be either positive or negative, depending on the junction being n-n type or p-n type. Based on the valley-dependent negative Refraction, a spin splitter (valley splitter) is designed at the p-n junction system, where the spin-up and spin-down electrons are focused at different regions. These findings may be useful for the engineering of double lenses in electronic system and have underlying application of spin splitter in spintronics.
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Double Refraction and spin splitter in normal-conductor/hexagonal-semiconductor junctions
Physical Review B, 2018Co-Authors: Peng LvAbstract:In analogy with Light Refraction at optical boundary, ballistic electrons also undergo Refraction when propagate across a semiconductor junction. Establishing a negative refractive index in conventional optical materials is difficult, but the realization of negative Refraction in electronic system is conceptually straightforward, which has been verified in graphene p-n junctions in recent experiments. Here, we propose a model to realize double Refraction and double focusing of electric current by a normal-hexagonal semiconductor junction. The double Refraction can be either positive or negative, depending on the junction being n-n type or p-n type. Based on the valley-dependent negative Refraction, a spin splitter (valley splitter) is designed at the p-n junction system, where the spin-up and spin-down electrons are focused at different regions. These findings may be useful for the engineering of double lenses in electronic system and have underlying application of spin splitter in spintronics.
Ruben G Barrera - One of the best experts on this subject based on the ideXlab platform.
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rigorous theoretical framework for particle sizing in turbid colloids using Light Refraction
Optics Express, 2008Co-Authors: Augusto Garciavalenzuela, Ruben G Barrera, Edahi GutierrezreyesAbstract:Using a non-local effective-medium approach, we analyze the Refraction of Light in a colloidal medium. We discuss the theoretical grounds and all the necessary precautions to design and perform experiments to measure the effective refractive index in dilute colloids. As an application, we show that it is possible to retrieve the size of small dielectric particles in a colloid by measuring the complex effective refractive index and the volume fraction occupied by the particles.
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measurement of the effective refractive index of a turbid colloidal suspension using Light Refraction
New Journal of Physics, 2005Co-Authors: Alejandro Reyescoronado, Augusto Garciavalenzuela, C Sanchezperez, Ruben G BarreraAbstract:We propose and analyse a simple method to measure simultaneously the real and imaginary parts of the effective refractive index of a turbid suspension of particles. The method is based on measurements of the angle of Refraction and transmittance of a laser beam that traverses a hollow glass prism filled with a colloidal suspension. We provide a comprehensive assessment of the method. It can offer high sensitivity while still being simple to interpret. We present results of experiments using an optically turbid suspension of polystyrene particles and compare them with theoretical predictions. We also report experimental evidence showing that the refractive behaviour of the diffuse component of Light coming from a suspension depends on the volume fraction of the colloidal particles.
Augusto Garciavalenzuela - One of the best experts on this subject based on the ideXlab platform.
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rigorous theoretical framework for particle sizing in turbid colloids using Light Refraction
Optics Express, 2008Co-Authors: Augusto Garciavalenzuela, Ruben G Barrera, Edahi GutierrezreyesAbstract:Using a non-local effective-medium approach, we analyze the Refraction of Light in a colloidal medium. We discuss the theoretical grounds and all the necessary precautions to design and perform experiments to measure the effective refractive index in dilute colloids. As an application, we show that it is possible to retrieve the size of small dielectric particles in a colloid by measuring the complex effective refractive index and the volume fraction occupied by the particles.
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measurement of the effective refractive index of a turbid colloidal suspension using Light Refraction
New Journal of Physics, 2005Co-Authors: Alejandro Reyescoronado, Augusto Garciavalenzuela, C Sanchezperez, Ruben G BarreraAbstract:We propose and analyse a simple method to measure simultaneously the real and imaginary parts of the effective refractive index of a turbid suspension of particles. The method is based on measurements of the angle of Refraction and transmittance of a laser beam that traverses a hollow glass prism filled with a colloidal suspension. We provide a comprehensive assessment of the method. It can offer high sensitivity while still being simple to interpret. We present results of experiments using an optically turbid suspension of polystyrene particles and compare them with theoretical predictions. We also report experimental evidence showing that the refractive behaviour of the diffuse component of Light coming from a suspension depends on the volume fraction of the colloidal particles.
Endi Suhendi - One of the best experts on this subject based on the ideXlab platform.
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the development of critical thinking skills and collaborative skill profiles aided by multimedia based integrated instruction on Light Refraction material
Universal Journal of Educational Research, 2020Co-Authors: Parsaoran Siahaan, Yusa Chavez Setiawan, N J Fratiwi, A Samsudin, Endi SuhendiAbstract:Along with the rapid development of technology in the 21st century, students are not only required to understand the cognitive aspects, but also skills such as critical thinking and collaboration that are important to be trained so that they have an ability to adapt quickly. Critical thinking and collaborative skills can be trained on students with learning that is integrated with computer multimedia. This study was aimed at identifying the improvement of critical thinking skills and the profile of students' collaborative skills using multimedia-based integrated instruction (MBI2). The research method used was Pre-Experimental with One Group Pretest Posttest Design. The participants of this study involved 33 students (consisting of 13 boys and 20 girls) in grade VIII in one state junior high school in Bandung. The results showed that the increase in students' critical thinking skills was in the medium category with an N-gain value = 0.42 and the collaborative skills profile of the students was in the good category. Based on the results of this study, it can be concluded that the use of MBI2 learning can develop critical thinking and collaborative skills of secondary school students on Light Refraction material.