scholarly journals Hydrothermal Synthesis of CeO2-SnO2 Nanoflowers for Improving Triethylamine Gas Sensing Property

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1025 ◽  
Author(s):  
Dongping Xue ◽  
Yan Wang ◽  
Jianliang Cao ◽  
Zhanying Zhang
Keyword(s):  
Gas Sensing ◽  
Hydrothermal Reaction ◽  
Pure Sno2 ◽  
Characterization Methods ◽  
Working Temperature ◽  
Wide Range ◽  
Sensitivity And Selectivity ◽  
One Step ◽  
The One ◽  
Optimum Working

Developing the triethylamine sensor with excellent sensitivity and selectivity is important for detecting the triethylamine concentration change in the environment. In this work, flower-like CeO2-SnO2 composites with different contents of CeO2 were successfully synthesized by the one-step hydrothermal reaction. Some characterization methods were used to research the morphology and structure of the samples. Gas-sensing performance of the CeO2-SnO2 gas sensor was also studied and the results show that the flower-like CeO2-SnO2 composite showed an enhanced gas-sensing property to triethylamine compared to that of pure SnO2. The response value of the 5 wt.% CeO2 content composite based sensor to 200 ppm triethylamine under the optimum working temperature (310 °C) is approximately 3.8 times higher than pure SnO2. In addition, CeO2-SnO2 composite is also significantly more selective for triethylamine than pure SnO2 and has better linearity over a wide range of triethylamine concentrations. The improved gas-sensing mechanism of the composites toward triethylamine was also carefully discussed.

Schottky diodes based on 2D materials for environmental gas monitoring: a review on emerging trends, recent developments and future perspectives

2021 ◽  
Author(s):  
Minu Mathew ◽  
Chandra Sekhar Rout
Keyword(s):  
Gas Sensing ◽  
2D Materials ◽  
Schottky Diodes ◽  
High Sensitivity ◽  
Future Perspectives ◽  
Working Temperature ◽  
Emerging Trends ◽  
Gas Sensing Properties ◽  
Recent Developments ◽  
Sensitivity And Selectivity

This review details the fundamentals, working principles and recent developments of Schottky junctions based on 2D materials to emphasize their improved gas sensing properties including low working temperature, high sensitivity, and selectivity.

scholarly journals A highly selective and sensitive H2S sensor at low temperatures based on Cr-doped α-Fe2O3 nanoparticles

RSC Advances ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 4150-4156 ◽  
Author(s):  
Dongyang Xue ◽  
Rui Zhou ◽  
Xiaoping Lin ◽  
Xiaochuan Duan ◽  
Qiuhong Li ◽  
...  
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Hydrothermal Reaction ◽  
High Sensitivity ◽  
Fe2o3 Nanoparticles ◽  
Sensitivity And Selectivity ◽  
One Step

Cr-doped α-Fe2O3 nanoparticles were synthesized by one-step hydrothermal reaction and showed high sensitivity and selectivity to H2S at low temperature.

scholarly journals Eco Friendly Synthesis of Carbon Dot by Hydrothermal Method for Metal Ions Salt Identification

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7604
Author(s):  
Hasan Shabbir ◽  
Tomasz Tokarski ◽  
Ditta Ungor ◽  
Marek Wojnicki
Keyword(s):  
Metal Ion ◽  
Hydrothermal Reaction ◽  
Synthesis Method ◽  
Emission Spectra ◽  
Carbon Quantum Dots ◽  
Photoluminescence Properties ◽  
Step Method ◽  
Synthesis Time ◽  
One Step ◽  
The One

In this work, we report the synthesis method of carbon quantum dots (CDs) using the one-step method for fast and effective metal ion determination. Ascorbic acid was used as an inexpensive and environmentally friendly precursor. High-pressure and high-temperature reactors were used for this purpose. Microscopic characterization revealed the size of CDs was in the range of 2–6 nm and they had an ordered structure. The photoluminescence properties of the CDs depend on the process temperature, and we obtained the highest PL spectra for 6 h of hydrothermal reaction. The maximum emission spectra depend poorly on synthesis time. Further characterization shows that CDs are a good contender for sensing Fe3+ in aqueous systems and can detect concentrations up to 0.49 ppm. The emission spectra efficiency was enhanced by up to 200% with synthesis time.

scholarly journals Highly Sensitive, Selective, Flexible and Scalable Room-Temperature NO2 Gas Sensor Based on Hollow SnO2/ZnO Nanofibers

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6475
Author(s):  
Jiahui Guo ◽  
Weiwei Li ◽  
Xuanliang Zhao ◽  
Haowen Hu ◽  
Min Wang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Positive Impact ◽  
High Sensitivity ◽  
Detection Sensitivity ◽  
Pure Sno2 ◽  
Flexible Devices ◽  
Low Concentrations ◽  
Highly Sensitive ◽  
Sensitivity And Selectivity

Semiconducting metal oxides can detect low concentrations of NO2 and other toxic gases, which have been widely investigated in the field of gas sensors. However, most studies on the gas sensing properties of these materials are carried out at high temperatures. In this work, Hollow SnO2 nanofibers were successfully synthesized by electrospinning and calcination, followed by surface modification using ZnO to improve the sensitivity of the SnO2 nanofibers sensor to NO2 gas. The gas sensing behavior of SnO2/ZnO sensors was then investigated at room temperature (~20 °C). The results showed that SnO2/ZnO nanocomposites exhibited high sensitivity and selectivity to 0.5 ppm of NO2 gas with a response value of 336%, which was much higher than that of pure SnO2 (13%). In addition to the increase in the specific surface area of SnO2/ZnO-3 compared with pure SnO2, it also had a positive impact on the detection sensitivity. This increase was attributed to the heterojunction effect and the selective NO2 physisorption sensing mechanism of SnO2/ZnO nanocomposites. In addition, patterned electrodes of silver paste were printed on different flexible substrates, such as paper, polyethylene terephthalate and polydimethylsiloxane using a facile screen-printing process. Silver electrodes were integrated with SnO2/ZnO into a flexible wearable sensor array, which could detect 0.1 ppm NO2 gas after 10,000 bending cycles. The findings of this study therefore open a general approach for the fabrication of flexible devices for gas detection applications.

Address of the President Lord Todd, O. M. at the Anniversary Meeting, 1 December 1980

1980 ◽  
Vol 211 (1182) ◽  
pp. 1-13 ◽  
Keyword(s):  
Usnic Acid ◽  
Chemical Properties ◽  
Wide Range ◽  
One Step ◽  
Oxidative Processes ◽  
The One ◽  
Physical And Chemical ◽  
Biosynthetic Studies ◽  
And Chemical Properties

The Copley Medal is awarded to Sir Derek Barton, F. R. S. Among Sir Derek Barton's many distinguished contributions to organic chemistry, outstanding is his conception and development of conformational analysis, which represents the most important advance in this century in the understanding of the stereochemistry of organic compounds, and for which he received a Nobel Prize in 1969. Originally devised for cyclohexane derivatives, the concept was rapidly extended to other ring systems, and is of major importance in interpretation of the physical and chemical properties of a wide range of natural products. Sir Derek has also contributed greatly to the understanding of biosynthesis, and in many cases demonstrated the validity of his hypotheses by labelling experiments in vivo . In particular, his ideas on the nature of phenolic coupling, involving one-electron oxidative processes, formed the basis of a very large number of successful biosynthetic studies, especially in the alkaloid field. He has also applied his ideas to the simulation of natural biosynthetic sequences, the one-step synthesis of the complex usnic acid from a simple monocyclic precursor providing one of the most striking examples.

scholarly journals A Straightforward Substitution Strategy to Tune BODIPY Dyes Spanning the Near-Infrared Region via Suzuki–Miyaura Cross-Coupling

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1297 ◽  
Author(s):  
Guanglei Li ◽  
Yu Otsuka ◽  
Takuya Matsumiya ◽  
Toshiyuki Suzuki ◽  
Jianye Li ◽  
...  
Keyword(s):  
Near Infrared ◽  
Cross Coupling ◽  
Cumulus Cells ◽  
Infrared Region ◽  
Quantum Yields ◽  
Nir Dyes ◽  
Wide Range ◽  
One Step ◽  
The One ◽  
First Time

In this study, a series of new red and near-infrared (NIR) dyes derived from 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) were developed by introducing thiophene and its derivatives to the 3- and 5- positions of the dichloroBODIPY core. For the first time, cyclictriol boronates and N-methyliminodiacetic acid (MIDA) boronate were used as organoboron species to couple with 3,5-dichloroBODIPY via the one-step Suzuki–Miyaura cross-coupling. Six kinds of thieno-expended BODIPY dyes were synthesized in acceptable yields ranging from 31% to 79%. All six dyes showed different absorption and emission wavelengths spanning a wide range (c.a. 600–850 nm) in the red and NIR regions with relatively high quantum yields (19–85%). Cellular imaging of 8-(2,6-dimethylphenyl)-re3,5-di(2-thienyl)-BODIPY (dye 1) was conducted using bovine cumulus cells, and the fluorescence microscopy images indicated that the chromophore efficiently accumulated and was exclusively localized in the cytoplasm, suggesting it could be utilized as a subcellular probe. All six dyes were characterized using 1H-NMR and mass spectrometry.

scholarly journals The role of thermal activation in motion and force generation by molecular motors

2000 ◽  
Vol 355 (1396) ◽  
pp. 511-522 ◽  
Author(s):  
R. Dean Astumian
Keyword(s):  
Molecular Motors ◽  
Atp Hydrolysis ◽  
Force Production ◽  
Hand Model ◽  
Small Load ◽  
Wide Range ◽  
One Step ◽  
The One ◽  
Kinesin Molecule ◽  
Stochastic Properties

The currently accepted mechanism for ATP–driven motion of kinesin is called the hand–over–hand model, where some chemical transition during the ATP hydrolysis cycle stretches a spring, and motion and force production result from the subsequent relaxation. It is essential in this mechanism for the moving head of kinesin to dissociate, while the other head remains firmly attached to the microtubule. Here we propose an alternative Brownian motor model where the action of ATP modulates the interaction potential between kinesin and the microtubule rather than a spring internal to the kinesin molecule alone. In this model neither head need dissociate (which predicts that under some circumstances a single–headed kinesin can display processive motion) and the transitions by which the motor moves are best described as thermally activated steps. This model is consistent with a wide range of experimental data on the force–velocity curves, the one ATP to one–step stoichiometry observed at small load, and the stochastic properties of the stepping.

scholarly journals Fast Response Isopropanol Sensing Properties with Sintered BiFeO3 Nanocrystals

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3829 ◽  
Author(s):  
Hongxiang Xu ◽  
Junhua Xu ◽  
Junlin Wei ◽  
Yamei Zhang
Keyword(s):  
Gas Sensing ◽  
Fast Response ◽  
Gas Detection ◽  
Detection Range ◽  
Sensing Properties ◽  
Working Temperature ◽  
Sensing Material ◽  
Gas Sensing Properties ◽  
Response And Recovery ◽  
Optimum Working

BiFeO3 nanocrystals were applied as the sensing material to isopropanol. The isopropanol sensor based on BiFeO3 nanocrystals shows excellent gas-sensing properties at the optimum working temperature of 240 °C. The sensitivity of as-prepared sensor to 100 ppm isopropanol is 31 and its response and recovery time is as fast as 6 and 17 s. The logarithmic curves of the sensitivity and concentration of BiFeO3 sensors are a very good linear in the low detection range of 2–100 ppm. In addition, the gas sensing mechanism is also discussed. The results suggest that the BiFeO3 nanomaterial can be potentially applied in isopropanol gas detection.

scholarly journals Preparation and Antitumor Activity of Betulin Dipropionate and its Composites

2021 ◽  
Vol 12 (5) ◽  
pp. 6873-6894
Keyword(s):  
Cancer Cells ◽  
Water Solubility ◽  
Annexin V ◽  
Birch Bark ◽  
Natural Polymers ◽  
Wide Range ◽  
One Step ◽  
High Cytotoxicity ◽  
Betulin Dipropionate ◽  
The One

Betulin dipropionate is a natural compound with high cytotoxicity toward many cancer cells. The one-step synthesis directly from the birch bark without a separate betulin isolation stage was developed to obtain betulin dipropionate. Due to its composition, betulin dipropionate is a promising drug for treating a wide range of diseases. However, the poor water solubility of this compound has limited its applications. We prepared the composites of betulin dipropionate using two methods: ball milling of the mixtures of betulin dipropionate with synthetic and natural polymers, such as polyvinylpyrrolidone polyethylene glycol, fumed silica, arabinogalactan, and preparation of thin films with arabinogalactan by evaporating the aqueous solutions. These composites showed higher water solubility and improved antitumor properties against ascites carcinoma cells and human lung adenocarcinoma cells compared with the initial substance. Furthermore, the cell viability studies based on Annexin V and Propidium iodide probes confirmed the high proapoptotic effect of betulin dipropionate against cancer cells.

General Trend of Negative Transference Number in Li Salt/Ionic Liquid Mixtures

2019 ◽  
Author(s):  
Nicola Molinari ◽  
Jonathan P. Mailoa ◽  
Boris Kozinsky
Keyword(s):  
Ionic Liquid ◽  
Transference Number ◽  
Liquid Mixtures ◽  
Single Linkage ◽  
Self Diffusion ◽  
Wide Range ◽  
Single Linkage Cluster ◽  
Concentrated Solution ◽  
The One ◽  
Dynamics Simulations

We show that strong cation-anion interactions in a wide range of lithium-salt/ionic liquid mixtures result in a negative lithium transference number, using molecular dynamics simulations and rigorous concentrated solution theory. This behavior fundamentally deviates from the one obtained using self-diffusion coefficient analysis and agrees well with experimental electrophoretic NMR measurements, which accounts for ion correlations. We extend these findings to several ionic liquid compositions. We investigate the degree of spatial ionic coordination employing single-linkage cluster analysis, unveiling asymmetrical anion-cation clusters. Additionally, we formulate a way to compute the effective lithium charge that corresponds to and agrees well with electrophoretic measurements and show that lithium effectively carries a negative charge in a remarkably wide range of chemistries and concentrations. The generality of our observation has significant implications for the energy storage community, emphasizing the need to reconsider the potential of these systems as next generation battery electrolytes.<br>

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