查找使用阿拉丁产品的科研文献

Temperature-Insensitive Gas Pressure Sensor Based on Photonic Crystal Fiber Interferometer

Ling Chen,Jiajun Tian,Qiang Wu,Jiewen Li,Yong Yao,Jiawei Wang

In situ enrichment amplification strategy enabling highly sensitive formaldehyde gas sensor

Lei Zhu,Jianan Wang,Jianwei Liu,Zhicheng Xu,Muhammad Salman Nasir,Xin Chen,Ze Wang,Shiyi Sun,Qianyue Ma,Jinbo Liu,Jiangtao Feng,Jidong Liang,Wei Yan

Rapid detection of hazardous trace gas is critical to protect humans from health threats. The current gas sensors, however, suffer from insufficient sensitivity and selectivity, which limits their use in the application of real-time monitoring for low concentration gas. Herein, a versatile “in situ enrichment amplification” (IEA) strategy is proposed, aiming to integrate the in situ formed adsorption-functional material for target gas enrichment and the backbone sensor-functional material for gas response. The IEA-based gas sensors exhibit high sensitivity and selectivity toward the detection of HCHO gas. The calculated detection limit of the IEA sensor to HCHO gas is 63 ppb, much lower than that of the conventional HCHO sensor (183 ppb). Furthermore, a wireless cloud HCHO detection system is developed to achieve sustainable remote monitoring of the HCHO gas. Application of this IEA strategy to other metal oxide sensing materials generates similarly successful results.

Gas exfoliation mechanisms of graphitic carbon nitride into few-layered nanosheets

Zheng Tao,Li Meisheng,Zhou Shouyong,Zhao Yijiang,Zhong Zhaoxiang,Chen Chenglung

Two-dimensional (2D) graphitic carbon nitride (g-C 3 N 4 ) nanosheets are widely used in photocatalysis, energy storage and membrane separation owing to their high specific surface area, rapid photogenic carrier migration rate and numerous active sites. In this study, high performance g-C 3 N 4 nanosheets with a particle size of about 290 nm were prepared by gas exfoliation. It was observed that the structure and properties of g-C 3 N 4 nanosheets prepared at 500 °C were superior as compared to 300 °C and 400 °C. The state of g-C 3 N 4 layers at different temperatures was also studied by molecular dynamics simulation. It was revealed that the liquid nitrogen (L-N 2 ) molecules could only penetrate the edge space between g-C 3 N 4 layers at 500 °C, however, no penetration took place in the layers. The traditional gas exfoliation mechanisms were observed to be incapable in explaining this phenomenon. Combining the experimental studies and molecular dynamics simulations, a novel gas exfoliation mechanism was proposed in this study so as to prepare few-layered g-C 3 N 4 nanosheets. Based on this, the L-N 2 molecules entered the edge space in g-C 3 N 4 layers and subsequently pushed deeper to exfoliate the nanosheets.

Effect of ultrasonication on rising characteristics of a single gas bubble

Yannan Liang,Hainan Wang,Ruoqian Zhou,Danlong Li,Haijun Zhang

In recent years, ultrasonication has been used to enhance flotation process. Gas bubble is the unique carrier during mineral flotation, and thus its characteristics play an important role. However, the bubble rising characteristics under ultrasound action are not clear. Therefore, this paper aims to investigate the effect of ultrasonication on bubble rising behaviors in deionized water and MIBC (Methyl Isobutyl Carbinol) solution. A laboratory visualization system of bubble motion with ultrasonication was designed based on the high-speed dynamic video technology to record the bubble rising process and analyze bubble rising characteristics. Bubble aspect ratio was found to increase with the surfactant concentration increasing, but the rising velocity was in opposite state. In each solution, a significantly higher bubble sphericity was observed with ultrasonication than that without ultrasonication, conversely, the bubble rising velocity was smaller under the action of ultrasonication. A roughly negative linear relationship was found between the bubble shape and rising velocity, and the ultrasonication diminished this relationship. Marangoni effect was considered as the cause of MIBC affecting the bubble motion, and possible explanations of ultrasonication affecting the bubble motion were given from the perspective of bubble surface wave, cavitation bubble oscillation and sound radiation force.

Prompt Electronic Discrimination of Gas Molecules by Self-Heating Temperature Modulation

Meng Li,Chanunthorn Chananonnawathorn,Ning Pan,Saksorn Limwichean,Zanhong Deng,Mati Horprathum,Junqing Chang,Shimao Wang,Hideki Nakajima,Annop Klamchuen,Liang Li,Gang Meng

Though considerable progress has been achieved on gas molecule recognition by electronic nose (e-nose) comprised of nonselective (metal oxide) semiconductor chemiresistors, extracting adequate molecular features within short time (<1 s) remains a big obstacle, which hinders the emerging e-nose applications in lethal or explosive gas warning. Herein, by virtue of the ultrafast (∼20 μs) thermal relaxation time of self-heated WO3-based chemiresistors fabricated via oblique angle deposition, instead of external heating, self-heating temperature modulation has been proposed to generate sufficient electrical response features. Accurate discrimination of 12 gases (including 3 xylene isomers with the same function group and molecular weight) has been readily achieved within 0.5–1 s, which is one order faster than the state-of-the-art e-noses. A smart wireless e-nose, capable of instantaneously discriminating target gas in ambient air background, has been developed, paving the way for the practical applications of e-nose in the area of homeland security and public health.

Determination of four residual solvents in cefepime by headspace gas chromatography

Le Wang

Objective To establish a headspace gas chromatography method to determine the residual solvents of methanol, acetone, dichloromethane, and toluene in cefepime. Methods Headspace gas chromatography using a DB-624 capillary column and temperature program was performed to detect four residual solvents in cefepime. The temperature program consisted of an initial temperature of 60 ℃maintained for 4 min, a temperature increased to 120 ℃ at 20 ℃·min −1 maintained for 3 min, and then a temperature increased to 200 ℃ at 40 ℃·min −1 maintained for 3 min. Results Linear relationships were found between the peak areas and mass concentrations of the four solvents mentioned above within the defined ranges. The limits of detection for methanol, acetone, dichloromethane and toluene were 0.50, 0.15, 0.10 and 0.08 mg·L -1 , respectively. The recoveries obtained using the standard addition method ranged from 98.41 % to 100.94 %. Conclusion This method demonstrated high sensitivity and good reproducibility, and it can be used to effectively control the residual amounts of methanol, acetone, dichloromethane, and toluene, to further improve the quality of cefepime.

GSH-Triggered/Photothermal-Enhanced H2S Signaling Molecule Release for Gas Therapy

Xinqiang Liang,Mekhrdod S. Kurboniyon,Yuanhan Zou,Kezong Luo,Shuhong Fang,Pengle Xia,Shufang Ning,Litu Zhang,Chen Wang

Traditional treatment methods for tumors are inefficient and have severe side effects. At present, new therapeutic methods such as phototherapy, chemodynamic therapy, and gasodynamic therapy have been innovatively developed. High concentrations of hydrogen sulfide (H2S) gas exhibit cancer-suppressive effects. Herein, a Prussian blue-loaded tetra-sulfide modified dendritic mesoporous organosilica (PB@DMOS) was rationally constructed with glutathione (GSH)-triggered/photothermal-enhanced H2S signaling molecule release properties for gas therapy. The as-synthesized nanoplatform confined PB nanoparticles in the mesoporous structure of organosilica silica due to electrostatic adsorption. In the case of a GSH overexpressed tumor microenvironment, H2S gas was controllably released. And the temperature increases due to the photothermal effects of PB nanoparticles, further enhancing H2S release. At the same time, PB nanoparticles with excellent hydrogen peroxide catalytic performance also amplified the efficiency of tumor therapy. Thus, a collective nanoplatform with gas therapy/photothermal therapy/catalytic therapy functionalities shows potential promise in terms of efficient tumor therapy.Keywords:gas therapy;H2S;GSH-triggered;Prussian blue;dendritic mesoporous organosilica

Construction of Co3O4/SnO2 yolk-shell nanofibers for acetone gas detection

Wanjing Wang,Jianbiao Xian,Jin Li,Mengfang Yu,Qiutian Duan,Chung Ming Leung,Min Zeng,Xingsen Gao

In this work, Co 3 O 4 /SnO 2 heterojunctions were proposed and fabricated by single-nozzle electrospinning. Interestingly, novel yolk-shell nanofibers could be formed in a proper doped content of Co 3 O 4 . The gas sensing properties of sensors based on Co 3 O 4 /SnO 2 yolk-shell nanofibers were evaluated, and a superior response of ∼216–100 ppm acetone at 350 °C was obtained. Additionally, Our sensors have an ultrafast response time of ∼0.62 s, demonstrating remarkable selectivity for acetone and excellent stability for both humidity and long-term use. These exceptional performances are attributed to the synergistic effect of nano-heterojunctions that enhance the effective interfacial area , as well as the unique yolk-shell structure of SnO 2 /Co 3 O 4 , which increases gas transport channels. Our results demonstrate that constructing Co 3 O 4 /SnO 2 yolk-shell nanofibers is an effective strategy for achieving high-performance acetone gas detection.

Effect of uniaxial stretching on gas separation performance of polyimide membranes

Guolong Huo,Zhiyong Guo,Zhiguang Zhang,Xiaowei Zhou,Junhao Xin,Yuchen Zhang,Shuanyan Kang,Yanqin Yang,Nanwen Li

Fine-tuning of the physical stacking structure for microporous polyimide (PI) membranes via the stretching processing is a practical way of achieving advanced membrane materials with improved aging resistance as well as high gas separation performance. Here, a fluorinated polyimide 6FDA:BPDA-TFDB(1:1:2) is used as a prototype and a series of stretched membranes X%-PI are fabricated by uniaxially stretching the membrane to different elongation ratio and then annealing. Based on birefringence and wide-angle X-ray diffraction measurements, it's found that regular orientation of polymer chains along the stretching direction and fine-tuning of d -spaces from interchain packing and π-π stacking happen during the uniaxial stretching process. As such, compared to pristine PI membrane, the stretched membranes show better mechanical and thermal stability, especially for the one with higher stretching ratio. In addition, owing to the increased packing density of polymer chains, the highly stretched membrane of 40%-PI shows significantly improved gas perm-selectivity by 32.8%, 24.3%, and 12.6% for He/CH 4 , H 2 /CH 4 , and CO 2 /CH 4 gas pairs, respectively, in comparison to pristine membrane. Furthermore, 40%-PI exhibits much higher gas permeability retention rate than that of other membranes after three months' aging. We expect that this work can offer polymer materials processing guidance for the preparation of high-performance gas separation membrane in future.

Convenient CNT-Paper Gas Sensors Prepared by a Household Inkjet Printer

Yan Yuan,Xiaolei Tang,Li Jiang,Yujie Yang,Yanhui Zhou,Yanmao Dong

A hydrosoluble light-sensitive polymer named PSAG (poly-styrenesulfonate acrylic acid glycidyl methacrylate) was synthesized by acrylic acid (AA), sodium 4-styrenesulfonate (SS), and glycidyl methacrylate (GMA). PSAG is used to modify multiwall carbon nanotubes (MWCNTs) with a length diameter between 0.004 and 0.016. An inkjet conductive ink was formed by well-dispersed MWCNTs in aqueous and organic solvents, which could adjust the surface tension and viscosity of the ink. Gas sensors were then fabricated using this conductive ink on a household inkjet printer. The sensors demonstrated good reproducibility and acceptable recovery time (<200 s) to ammonia, methanol, and acetone. The resistance of the inkjet-printed sensor electrodes remained stable in the process of bending the sensors to different angles because of ultraviolet curing.

ZnFe2O4/ZnO nanosheets assembled microspheres for high performance trimethylamine gas sensing

Cong Zheng,Cheng Zhang,Lifang He,Kui Zhang,Jian Zhang,Ling Jin,Abdullah M. Asiri,Khalid A. Alamry,Xiangfeng Chu

ZnFe 2 O 4 /ZnO nanosheets assembled microspheres (ZnFe 2 O 4 /ZnO SAS) were successfully constructed by hydrothermal synthesis of ZnO nanosheets assembled microsphere and subsequent growth of ZnFe 2 O 4 nanoparticles on it via a facile solution method. The morphologies and components of as-synthesized ZnFe 2 O 4 /ZnO SAS composites were varied with growth time, and ZnFe 2 O 4 /ZnO SAS composite with the growth time of 30 min (ZnFe 2 O 4 /ZnO SAS30) consisted of porous nanosheets assembled by small ZnFe 2 O 4 and ZnO nanoparticles. The composites were applied as sensing film for trimethylamine (TMA) sensing. ZnFe 2 O 4 /ZnO SAS30 based sensor exhibited good selectivity and higher response to TMA than that of sensors based on bare ZnO microspheres precursor, ZnO/ZnFe 2 O 4 nanoparticle composite and other ZnFe 2 O 4 /ZnO SAS composites, respectively. At 240 °C, the ZnFe 2 O 4 /ZnO SAS30 based sensor exhibited 31.5–100 ppm TMA with a quick response and recovery time of 3.1 s and 5.7 s, respectively, and even as low as 0.1 ppm TMA can be detected. Meanwhile, the corresponding cycling performance and stability was also checked. Such favorable comprehensive sensing performance of ZnFe 2 O 4 /ZnO SAS30 to TMA was attributed to its unique hierarchical structure and ZnO/ZnFe 2 O 4 heterojunctions . All results enabled potential applications of ZnFe 2 O 4 /ZnO SAS30 composite in TMA sensing.

Antibuoyancy and Unidirectional Gas Evolution by Janus Electrodes with Asymmetric Wettability

Siyu Sheng,Bairu Shi,Cheng Wang,Liang Luo,Xiao Lin,Pengsong Li,Fanhong Chen,Zhicheng Shang,Hong Meng,Yun Kuang,Wen-Feng Lin,Xiaoming Sun

The bubbles electrochemically generated by gas evolution reactions are commonly driven off the electrode by buoyancy, a weak force used to overcome bubble adhesion barriers, leading to low gas-transporting efficiency. Herein, a Janus electrode with asymmetric wettability has been prepared by modifying two sides of a porous stainless-steel mesh electrode, with superhydrophobic polytetrafluoroethylene (PTFE) and Pt/C (or Ir/C) catalyst with well-balanced hydrophobicity, respectively, affording unidirectional transportation of as-formed gaseous hydrogen and oxygen from the catalyst side to the gas-collecting side during water splitting. “Bubble-free” electrolysis was realized while “floating” the Janus electrode on the electrolyte. Antibuoyancy through-mesh bubble transportation was observed while immersing the electrode with the PTFE side downward. The wettability gradient within the electrode endowed sticky states of bubbles on the catalyst side, resulting in efficient bubble-free gas transportation with 15-fold higher current density than submerged states.