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991.
Carbon–Heteroatom Bond Formation by an Ultrasonic Chemical Reaction for Energy Storage Systems
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Hyun‐Tak Kim HyeonOh Shin In‐Yup Jeon Jaeyoon Baik Hae‐Won Cheong Noejung Park Jong‐Beom Baek Tae‐Hyuk Kwon 《Advanced materials (Deerfield Beach, Fla.)》2017,29(47)
The direct formation of C? N and C? O bonds from inert gases is essential for chemical/biological processes and energy storage systems. However, its application to carbon nanomaterials for improved energy storage remains technologically challenging. A simple and very fast method to form C? N and C? O bonds in reduced graphene oxide (RGO) and carbon nanotubes (CNTs) by an ultrasonic chemical reaction is described. Electrodes of nitrogen‐ or oxygen‐doped RGO (N‐RGO or O‐RGO, respectively) are fabricated via the fixation between N2 or O2 carrier gas molecules and ultrasonically activated RGO. The materials exhibit much higher capacitance after doping (133, 284, and 74 F g?1 for O‐RGO, N‐RGO, and RGO, respectively). Furthermore, the doped 2D RGO and 1D CNT materials are prepared by layer‐by‐layer deposition using ultrasonic spray to form 3D porous electrodes. These electrodes demonstrate very high specific capacitances (62.8 mF cm?2 and 621 F g?1 at 10 mV s?1 for N‐RGO/N‐CNT at 1:1, v/v), high cycling stability, and structural flexibility. 相似文献
992.
Water Splitting: A Highly Versatile and Adaptable Artificial Leaf with Floatability and Planar Compact Design Applicable in Various Natural Environments (Adv. Mater. 34/2017)
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993.
Multi‐Drug‐Loaded Microcapsules with Controlled Release for Management of Parkinson's Disease
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Jong‐Suep Baek Chee Chong Choo Cheng Qian Nguan Soon Tan Zexiang Shen Say Chye Joachim Loo 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(27):3712-3722
Parkinson's disease (PD) is a progressive disease of the nervous system, and is currently managed through commercial tablets that do not sufficiently enable controlled, sustained release capabilities. It is hypothesized that a drug delivery system that provides controlled and sustained release of PD drugs would afford better management of PD. Hollow microcapsules composed of poly‐l ‐lactide (PLLA) and poly (caprolactone) (PCL) are prepared through a modified double‐emulsion technique. They are loaded with three PD drugs, i.e., levodopa (LD), carbidopa (CD), and entacapone (ENT), at a ratio of 4:1:8, similar to commercial PD tablets. LD and CD are localized in both the hollow cavity and PLLA/PCL shell, while ENT is localized in the PLLA/PCL shell. Release kinetics of hydrophobic ENT is observed to be relatively slow as compared to the other hydrophilic drugs. It is further hypothesized that encapsulating ENT into PCL as a surface coating onto these microcapsules can aid in accelerating its release. Now, these spray‐coated hollow microcapsules exhibit similar release kinetics, according to Higuchi's rate, for all three drugs. The results suggest that multiple drug encapsulation of LD, CD, and ENT in gastric floating microcapsules could be further developed for in vivo evaluation for the management of PD. 相似文献
994.
This paper investigated the green synthesis of silver nanoparticles (AgNPs) using aqueous extract of silky hairs of corn (Zea mays L.) which is a waste material of the crop, as both a reducing and stabilising/capping agent. The AgNPs were characterised by UV‐visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X‐ray analysis (EDX), thermogravimetric analysis (TGA), X‐ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT‐IR). The average size of AgNPs was found to be 249.12 nm. The AgNPs displayed strong antibacterial activity against five different foodborne pathogenic bacteria with diameter of inhibition zones ranged between (9.23 − 12.81 mm). It also exhibited potent synergistic antibacterial activity together with standard antibiotics, kanamycin (10.6 − 13.65 mm inhibition zones) and rifampicin (10.02 − 12.86 mm inhibition zones) and anticandidal activity with amphotericin b (10.57 − 13.63 mm inhibition zones). The AgNPs exhibited strong antioxidant activity in terms of nitric oxide scavenging (IC50 91.56 µg/mL), ABTS (2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) radical scavenging (IC50 115.75 µg/mL), DPPH (1,1‐diphenyl‐2‐picrylhydrazyl) radical scavenging (IC50 385.87 µg/mL), and reducing power (IC0.5 23.14 µg/mL). This study demonstrated the synthesis of spherical AgNPs with strong antibacterial, anticandidal and antioxidant properties that could potentially be utilised in the biomedical, cosmetic, food and pharmaceutical industries.Inspec keywords: silver, nanoparticles, nanomedicine, antibacterial activity, biomedical materials, nanofabrication, botany, ultraviolet spectra, visible spectra, scanning electron microscopy, X‐ray chemical analysis, Fourier transform infrared spectra, crystallitesOther keywords: biomedical industry, cosmetic industry, food industry, pharmaceutical industry, Ag, crystallite size, 1,1‐diphenyl‐2‐picrylhydrazyl radical scavenging, 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) radical scavenging, nitric oxide scavenging, amphotericin b, anticandidal activity, rifampicin, kanamycin, standard antibiotics, inhibition zones, foodborne pathogenic bacteria, Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, energy‐dispersive X‐ray analysis, scanning electron microscopy, ultraviolet‐visible spectroscopy, Zea mays L, antioxidant potential, anticandidal synergistic activity, antibacterial synergistic activity, corn, silky hair aqueous extract, silver nanoparticles biosynthesis 相似文献
995.
Hong Il Kim Se-Woong Baek Min-Jae Choi Bin Chen Olivier Ouellette Kyoungwon Choi Benjamin Scheffel Hyuntae Choi Margherita Biondi Sjoerd Hoogland F. Pelayo García de Arquer Taiho Park Edward H. Sargent 《Advanced materials (Deerfield Beach, Fla.)》2020,32(42):2004657
Monolithically integrated hybrid tandem solar cells (TSCs) that combine solution-processed colloidal quantum dot (CQD) and organic molecules are a promising device architecture, able to complement the absorption across the visible to the infrared. However, the performance of organic/CQD hybrid TSCs has not yet surpassed that of single-junction CQD solar cells. Here, a strategic optical structure is devised to overcome the prior performance limit of hybrid TSCs by employing a multibuffer layer and a dual near-infrared (NIR) absorber. In particular, a multibuffer layer is introduced to solve the problem of the CQD solvent penetrating the underlying organic layer. In addition, the matching current of monolithic TSCs is significantly improved to 15.2 mA cm−2 by using a dual NIR organic absorber that complements the absorption of CQD. The hybrid TSCs reach a power conversion efficiency (PCE) of 13.7%, higher than that of the corresponding individual single-junction cells, representing the highest efficiency reported to date for CQD-based hybrid TSCs. 相似文献
996.
Hong Il Kim Se-Woong Baek Hyung Jin Cheon Seung Un Ryu Seungjin Lee Min-Jae Choi Kyoungwon Choi Margherita Biondi Sjoerd Hoogland F. P. García de Arquer Soon-Ki Kwon Yun-Hi Kim Taiho Park Edward H. Sargent 《Advanced materials (Deerfield Beach, Fla.)》2020,32(48):2004985
The need for optoelectronic and chemical compatibility between the layers in colloidal quantum dot (CQD) photovoltaic devices remains a bottleneck in further increasing performance. Conjugated polymers are promising candidates as new hole-transport layer (HTL) materials in CQD solar cells (CQD-SCs) owing to the highly tunable optoelectronic properties and compatible chemistries. A diketopyrrolopyrrole-based polymer with benzothiadiazole derivatives (PD2FCT-29DPP) as an HTL in these devices is reported. The energy level, molecular orientation, and hole mobility of this HTL are manipulated through molecular engineering. By levering the polymer's optical absorption spectrum complementary to that of the CQD active layer, EQE across the visible and near-infrared regions is maximized. As a result, a PD2FCT-29DPP-based device exhibits a fill factor of 70% and approximately 35% efficiency enhancement compared to a PTB7-based device. 相似文献
997.
Hocheon Yoo Sungmin On Seon Baek Lee Kilwon Cho Jae‐Joon Kim 《Advanced materials (Deerfield Beach, Fla.)》2019,31(29)
Multivalued logic (MVL) computing could provide bit density beyond that of Boolean logic. Unlike conventional transistors, heterojunction transistors (H‐TRs) exhibit negative transconductance (NTC) regions. Using the NTC characteristics of H‐TRs, ternary inverters have recently been demonstrated. However, they have shown incomplete inverter characteristics; the output voltage (VOUT) does not fully swing from VDD to GND. A new H‐TR device structure that consists of a dinaphtho[2,3‐b:2′,3′‐f]thieno[3,2‐b]thiophene (DNTT) layer stacked on a PTCDI‐C13 layer is presented. Due to the continuous DNTT layer from source to drain, the proposed device exhibits novel switching behavior: p‐type off/p‐type subthreshold region /NTC/ p‐type on. As a result, it has a very high on/off current ratio (≈105) and exhibits NTC behavior. It is also demonstrated that an array of 36 of these H‐TRs have 100% yield, a uniform on/off current ratio, and uniform NTC characteristics. Furthermore, the proposed ternary inverter exhibits full VDD‐to‐GND swing of VOUT with three distinct logic states. The proposed transistors and inverters exhibit hysteresis‐free operation due to the use of a hydrophobic gate dielectric and encapsulating layers. Based on this, the transient operation of a ternary inverter circuit is demonstrated for the first time. 相似文献
998.
Perovskite oxides like SrTiO3 at the nanoscale are of interest for emerging applications,including high-k dielectrics and sensors.However,their synthesis requires long calcination at the elevated temperature,which is a barrier of their application to flexible electronics.Here,an effective laser-assisted sol-gel method to patternably produce SrTiO3 nanoparticles (-100 nm) in selective areas on polyimide substrates (coated with ITO) is introduced.Importantly,the violet-laser power is just 1 W but sufficient to crystallize the material in a short period (a few seconds).Furthermore,developing a flexible device platform using carbon nanotubes (CNT) and SrTiO3 nanoparticles for detection of humidity changes at room temperature is proposed.The sensor platform has both capacitive and resistive sensing abilities.The resistive mode with a lower power usage (about 0.2 μW) is suitable for long monitoring of humidity in the range of 2% RH and above.The capacitive mode with higher sensitivity,faster response/recovery time (1-3 min),and lower detection limit (0.5% RH) can be used for calibration purposes.The performance of the flexible sensor is still maintained after 5000 bending cycles at 1.5-cm radius.Altogether,our synthesis method and the flexible sensor show chances for mass-producing perovskite oxides at low cost for wearable electronics. 相似文献
999.
Seung Jung Yu Kwanyong Pak Moo Jin Kwak Munkyu Joo Bong Jun Kim Myung Seok Oh Jieung Baek Hongkeun Park Goro Choi Do Heung Kim Junhwan Choi Yunho Choi Jihye Shin Heeyeon Moon Eunjung Lee Sung Gap Im 《Advanced Engineering Materials》2018,20(3)
1000.
Reduction of DNA Folding by Ionic Liquids and Its Effects on the Analysis of DNA–Protein Interaction Using Solid‐State Nanopore
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Ki‐Baek Jeong Ke Luo Min‐Cheol Lim Jong‐Yoon Jung Jae‐Seok Yu Ki‐Bum Kim Young‐Rok Kim 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(31)
DNA folding is not desirable for solid‐state nanopore techniques when analyzing the interaction of a biomolecule with its specific binding sites on DNA since the signal derived from the binding site could be buried by a large signal from the folding of DNA nearby. To resolve the problems associated with DNA folding, ionic liquids (ILs), which are known to interact with DNA through charge–charge and hydrophobic interactions are employed. 1‐n‐butyl‐3‐methylimidazolium chloride (C4mim) is found to be the most effective in lowering the incident of DNA folding during its translocation through solid‐state nanopores (4–5 nm diameter). The rate of folding signals from the translocation of DNA–C4mim is decreased by half in comparison to that from the control bare DNA. The conformational changes of DNA upon complexation with C4mim are further examined using atomic force microscopy, showing that the entanglement of DNA which is common in bare DNA is not observed when treated with C4mim. The stretching effect of C4mim on DNA strands improves the detection accuracy of nanopore for identifying the location of zinc finger protein bound to its specific binding site in DNA by lowering the incident of DNA folding. 相似文献