On Two Parallel Matched Gratings Demodulation Method of Fiber Grating Strain Sensor

The method of demodulation with two parallel matched fiber Bragg gratings( FBGs)system is introduced to enlarge the range of strain that can be detected by the FBG sensor system.     

A bubble detection technique based on light intensity and Mie scattering theory for spinning solution

A novel bubble detection technique based on light intensity and Mie scattering theory for spinning solution is presented theoretically and experimentally. With the light intensity in every direction, the particle or bubble size distribution can be calculated with the Mie scattering theory. The light intensity distribution in every direction, corresponding to the light intensity received by every assumed annulus of the detector has been calculated theoretically. According to the light intensity distribution, the size distribution of bubbles can be deduced. A series of standardized polystyrene micro-sphere (with 7 μm diameter) solution has been used not only as sample for experiments and calibration, but also as the bubbles in the glycerin. Theoretical and experimental results show that the technique can be used for bubble detection, in order to improve the traditional bubble detection scheme, and to lower production costs.     

A novel fiber Bragg grating high-temperature sensor

A novel fiber Bragg grating (FBG) sensor for the measurement of high temperature is proposed and experimentally demonstrated. The interrogation system of the sensor system is simple, low cost but effective. The sensor head is comprised of one FBG and two metal rods. The lengths of the rods are different from each other. The coefficients of thermal expansion of the rods are also different from each other. The FBG will be strained by the sensor head when the temperature to be measured changes. The temperature is measured basis of the wavelength shifts of the FBG induced by strain. A dynamic range of 0–800 °C and a resolution of 1 °C have been obtained by the sensor system. The experiment results agree with theoretical analyses.     

A multi-parameter optical fiber sensor with interrogation and discrimination capabilities

A multi-parameter and multi-function, but low-cost, optical fiber grating sensor with self-interrogation and self-discrimination capabilities is presented theoretically and experimentally. The sensor bases on three fiber Bragg gratings (FBG) and one fiber long period grating (LPG). Strain, vibration, pressure, ordinary temperature (−10 to 100 °C) and high temperature (100–800 °C) can be measured by the sensor. When high temperature (100–800 °C) is measured, the LPG is used as a high temperture sensor head and FBG₁ is used as an interrogation element. Alternatively, when one of the other four measurands is measured, FBG₁ (or FBG₂) is used as a sensor head and LPG is used as an interrogation element. When two of the other four measurands are measured simultaneously, FBG₁ and FBG₂ are used as sensor heads and LPG is used as a shared interrogation element. FBG₃ is used as a reference element to eliminate the errors resulted from light source fluctuation and the cross-sensitivity between measurand and environmental temperature. The measurands can be interrogated according to the signals of the photodiodes (PDs), which are related to the relative wavelength shift of the LPG and the FBGs. Experimental results agree well with theoretical analyses. The interrogation scheme is immune to light source fluctuation and the cross-sensitivity between measurands and enviromental temperature, and also the dynamic range is large.     

3M⊙ AGB星中26Al核合成的网络计算和反应率灵敏度分析

研究了3$M_{\odot}$AGB星中26Al核合成的网络计算和核反应率的灵敏度分析。结合最新的核反应率数据,建立了一个从碳到硅完整的核反应网络,计算了26Al的丰度。结果表明,26Al首先在AGB星中有效合成,随着核反应的进行,然后被一系列的核反应消耗。MgAl循环出现在26Al的网络中。我们将核反应网络中的主要核反应分为三类:(n, ${\rm{\gamma }}$),(p,${\rm{\gamma }}$)和($\alpha$, ${\rm{\gamma }}$),并对核反应率的灵敏度进行了详细的分析。已经确定了每一类中最有影响的核反应,它们是25Mg(n, ${\rm{\gamma }}$)26Mg,25Mg(p, ${\rm{\gamma }}$)26Al,26Mg(p, ${\rm{\gamma }}$)27Al,21Ne(p, ${\rm{\gamma }}$)22Na,18O($\alpha$, ${\rm{\gamma }}$)22Ne和22Ne($\alpha$,${\rm{\gamma }}$)26Mg。在目前网络所涉及的所有核反应中,25Mg(p, ${\rm{\gamma }}$)26Al是对26Al的产量有最大的影响,它值得核实验物理学家的关注。     

The ortho‐Difluoroalkylation of Aryliodanes with Enol Silyl Ethers: Rearrangement Enabled by a Fluorine Effect

Presented herein is an intriguing effect of fluorine, and it allows difluoroenol silyl ethers to couple with aryliodanes in a redox‐neutral manner to afford ortho‐iodo difluoroalkylated arenes. The remaining iodide group provides a versatile platform for converting the products into various valuable difluoroalkylated arenes. The reaction shows excellent functional‐group compatibility and broad substrate scope. A DFT mechanistic study suggests that the fluorine effect facilitates a subtle nucleophilic attack of the oxygen atom of enol silyl ethers onto aryliodanes, therefore leading to a rearrangement.     

Photostable lysosomal imaging of living cell with hyperspectral stimulated Raman scattering microscopy using a probe based on bisarylbutadiyne

Lysosome-selective Raman probe, Lyso-BADY, was created with improved Raman signal intensity, stability as well as specificity under the visualization of hyperspectral stimulated Raman scattering (SRS) microscopy. Prolonged exposure to irradiation further proved its photostability and potentiality for continuous imaging.     

Effects of Airflow Ultrafine-Grinding on the Physicochemical Characteristics of Tartary Buckwheat Powder

Five different ultrafine milled flours (UMFs) were prepared from Tartary buckwheat via airflow ultrafine-grinding at different grinding pressures. The airflow ultrafine-grinding resulted in marked differences in particle size (from 100 to 10 μm). The UMFs were all brighter in appearance (higher L*) than Tartary buckwheat common flour (TBCF). Illustrated by the example of 70 °C, the UMFs were also found to have a greater water holding capacity (from 4.42 g/g to 5.24 g/g), water solubility (from 12.57% to 14.10%), and water solubility index (from 5.11% to 6.10%). Moreover, as the particle sizes reduced, the moisture content decreased (from 10.05 g/100 g DW to 7.66 g/100 g DW), as did the total starch content (from 68.88 g/100 g DW to 58.24 g/100 g DW) and the protein content (from 13.16% to 12.04%). However, the grinding process was also found to have negative effects on the mineral content of the Tartary buckwheat. Additionally, several substantial variations were found in their hydration properties along with grinding pressure changes in the differently ground UMFs. Consequently, fine Tartary buckwheat powders of a bright yellow color, with superior food processing properties, were prepared in this study by airflow ultrafine-grinding.     

The Degradation of Beam Quality in Large-Core Optical Fiber

The degradation of beam quality in large-core fiber is investigated experimentally. It is found that the output beam quality factor M2 is a compound tanh function ofthe fiber lengths and misalignment launch results that the beam quality degraded faster.     

Electrogenerated chemiluminescence aptamer-based method for the determination of thrombin incorporating quenching of tris(2,2-bipyridine)ruthenium by ferrocene

A novel electrogenerated chemiluminescence (ECL) aptamer-based biosensing method for the determination of thrombin was developed on basis of a structure-switching ECL-dequenching mechanism. A thiolated ss-DNA capture probe, composing of a ss-DNA sequence to adopt two distinct structures-a DNA double strand with a complementary DNA sequence tagged with a ECL signal producer tris(2,2^′-bipyridyl)ruthenium derivative and a DNA duplex with a thrombin-binding aptamer tagged with a ECL-quencher ferrocene (FcDNA), was self-assembled onto surface of a gold electrode. In the presence of thrombin, the aptamer sequence prefers to form the aptamer-thrombin complex and the switch of the binding partners occurs in conjunction with the generation of a strong ECL signal owing to the dissociation of FcDNA. The integrated ECL intensity versus the concentration of thrombin was linear in the range from 2.0 × 10⁻¹⁰ M to 2.0 × 10⁻⁷ M. The detection limit was 6 × 10⁻¹¹ M. The relative standard derivation for 2.0 × 10⁻⁹ M was 5.7% (n = 7). This work demonstrates that the sensitivity and specificity of ECL aptamer-based method for proteins can be greatly improved using quenching ECL signal producer by a chemical quencher such as ferrocene.