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排序方式: 共有246条查询结果,搜索用时 15 毫秒
1.
Leqing Lin Yu Zhong Haoyang Lin Chenglong Wang Zhifei Yang Qian Wu Di Zhang Wenguo Zhu Yongchun Zhong Yuwei Pan Jianhui Yu Huadan Zheng 《Molecules (Basel, Switzerland)》2022,27(13)
Spider silk is one of the hottest biomaterials researched currently, due to its excellent mechanical properties. This work reports a novel humidity sensing platform based on a spider silk-modified quartz tuning fork (SSM-QTF). Since spider silk is a kind of natural moisture-sensitive material, it does not demand additional sensitization. Quartz-enhanced conductance spectroscopy (QECS) was combined with the SSM-QTF to access humidity sensing sensitively. The results indicate that the resonance frequency of the SSM-QTF decreased monotonously with the ambient humidity. The detection sensitivity of the proposed SSM-QTF sensor was 12.7 ppm at 1 min. The SSM-QTF sensor showed good linearity of ~0.99. Using this sensor, we successfully measured the humidity of disposable medical masks for different periods of wearing time. The results showed that even a 20 min wearing time can lead to a >70% humidity in the mask enclosed space. It is suggested that a disposable medical mask should be changed <2 h. 相似文献
2.
In this research, we focuses on a new detection method for testing a micro electro mechanical systems V-shaped groove in silicon using spectral domain optical coherence tomography with a thermal light source. By this method, the V-shaped groove depth, width and bottom width were measured. The technique, because of its noncontact operation and high acquisition rate, is suitable for on-line precision measurement of V-shaped grooves in silicon. 相似文献
3.
Yuwei Gu Julia Zhao Jeremiah A. Johnson 《Angewandte Chemie (International ed. in English)》2020,59(13):5022-5049
Polymer networks, which are materials composed of many smaller components—referred to as “junctions” and “strands”—connected together via covalent or non‐covalent/supramolecular interactions, are arguably the most versatile, widely studied, broadly used, and important materials known. From the first commercial polymers through the plastics revolution of the 20th century to today, there are almost no aspects of modern life that are not impacted by polymer networks. Nevertheless, there are still many challenges that must be addressed to enable a complete understanding of these materials and facilitate their development for emerging applications ranging from sustainability and energy harvesting/storage to tissue engineering and additive manufacturing. Here, we provide a unifying overview of the fundamentals of polymer network synthesis, structure, and properties, tying together recent trends in the field that are not always associated with classical polymer networks, such as the advent of crystalline “framework” materials. We also highlight recent advances in using molecular design and control of topology to showcase how a deep understanding of structure–property relationships can lead to advanced networks with exceptional properties. 相似文献
4.
Design of diamond-shape photonic crystal fiber polarization filter based on surface plasma resonance effect 下载免费PDF全文
A novel plasmonic polarization filter based on the diamond-shape photonic crystal fiber(PCF) is proposed. The resonant coupling characteristics of the PCF polarization filter are investigated by the full-vector finite-element method. By optimizing the geometric parameters of the PCF, when the fiber length is 5 mm, the polarization filter has a bandwidth of 990 nm and an extinction ratio(ER) of lower than -20 dB. Moreover, a single wavelength polarization filter can also be achieved, along with an ER of -279.78 dB at wavelength 1.55 μm. It is believed that the proposed PCF polarization filter will be very useful in laser and optical communication systems. 相似文献
5.
Qianqian Sun Yuwei Long Hongxi Li Shuang Pan Jidong Yang Shaopu Liu Xiaoli Hu 《Journal of fluorescence》2018,28(2):523-531
Caffeic acid (CA), a familiar color stabilizing reagent, has aroused general concern due to its uncontrolled addition, and thus the detection of CA is increasingly important. In our report, the bright carbon dots (CDs) were prepared via hydrothermal treatment with urea and citric acid act as raw material and their characteristics were discussed through X-ray diffraction (XRD), transmission electron microscopy (TEM) and so on. Impressively, the strong emission of the as-prepared CDs (Quantum Yield: 24.3%) decreased sharply upon a full reaction with the added CA. Hence, we first present an improved strategy for determining CA based upon the quenching of the strong emission of CDs. In this strategy, 0.79–100.0 µmol L??1 caffeic acid could be simply detected, and a detection limit of 0.24 µmol L??1 was allowed. Additionally, CA in red wine samples can be successfully detected by this method and the exploration of the quenching mechanism of the CA-CDs system was done. 相似文献
6.
Jihong Chen Yuwei Li Baoshan Zhang Yi Yang Mu Lu Huaixian Lu 《Journal of magnetism and magnetic materials》2010,322(20):3109-3111
[NiO/Fe65Co35]10 exchange-coupled multilayer films for high frequency applications are fabricated, and their static magnetic property and microwave permeability are studied systematically. Both exchange bias field and ferromagnetic resonance frequency of the multilayers increase with decreasing Fe65Co35 thickness, which means that the microwave properties such as permeability and FMR frequency can be controlled by changing Fe65Co35 thickness in the exchange-coupled films. Ferromagnetic resonance frequencies beyond 7 GHz of the films are measured and reported for the first time. 相似文献
7.
8.
In this paper, we propose a globally hyperbolic regularization to the general Grad's moment system in multidimensional spaces. Systems with moments up to an arbitrary order are studied. The characteristic speeds of the regularized moment system can be analytically given and depend only on the macroscopic velocity and the temperature. The structure of the eigenvalues and eigenvectors of the coefficient matrix is fully clarified. The regularization together with the properties of the resulting moment systems is consistent with the simple one‐dimensional case discussed in 1. In addition, all characteristic waves are proven to be genuinely nonlinear or linearly degenerate, and the studies on the properties of rarefaction waves, contact discontinuities, and shock waves are included. © 2014 Wiley Periodicals, Inc. 相似文献
9.
基于快速有效的基质净化方法,结合超高效液相色谱-串联质谱技术,建立了测定蜂蜜中39种抗生素及25种农药的检测方法.蜂蜜样品经乙腈+水(v/v=8:2)提取,用PRiME HLB净化,超高效液相色谱-串联质谱(ultra-performance liquid chromatography tandem mass spectrometry,UPLC-MS/MS)分析测定,通过多反应监测模式(MRM)分析目标化合物,并进行基质标准曲线定量.在测定浓度范围内呈良好线性关系,相关系数大于0.99;农兽药的检出限为0.02~3.8 μg·kg-1,定量限为0.1~11.5 μg·kg-1;在3档浓度的添加回收实验中,39种抗生素的回收率在72%~119%内,25种农药的回收率在72%~115%内,相对标准偏差均小于15%.随机抽取浙江市场上在售的52份蜂蜜样进行检测分析和膳食暴露评估,共检出罗红霉素、诺氟沙星和环丙沙星3种抗生素,检出率分别为2.6%,8.6%和3.9%,浓度分别为59.6~214.4,4.7~1 486.3和5.9~215.1 μg·kg-1.膳食暴露评估结果表明,蜂蜜中抗生素残留对10岁以下组群的风险高于其他组群、女性消费者高于男性消费者;% ADI<100,说明膳食暴露评估风险水平尚可接受.因在计算中存在诸多不确定性因素,对组群的风险评估尚需进一步分析. 相似文献
10.
Li Q Zhao C Li Y Chang Y Wu Z Pang T Lu X Wu Y Xu G 《Journal of separation science》2011,34(2):119-126
An approach was developed for extracting and analyzing the chemical components of tobacco leaves based on solvent extraction and rapid & resolution liquid chromatography/quadrupole time-of-flight mass spectrometry analysis. Two solvents with different polarities were used to extract hydrophilic components and hydrophobic components, respectively, the combined analytical data can provide a "global" view of metabolites. Based on the evaluation of parallel samples, it was found that this approach provided good repeatability, accurate and reliable profiling data, and is suitable for the metabolomics study of tobacco leaves. In order to find the chemical component differences of tobacco leaves, 56 samples from Zimbabwe and China were analyzed using the developed method. The metabolite data were processed by multivariate statistic technique; an obvious group classification between Zimbabwe and China was observed, 14 significantly changed compounds were found, and 9 of them were identified. 相似文献