TiO2/CuInS2-sensitized structure for sensitive photoelectrochemical immunoassay of cortisol in saliva

Journal of Solid State Electrochemistry - Cortisol, a steroid hormone, has been confirmed as a kind of biomarker that reflects the stress response of psychobiology and related adverse health...     

气相色谱法测定人体血液中乙醇含量的测量不确定度评定

对气相色谱法测定人体血液中乙醇含量的测量不确定度进行评定。人体血液中乙醇含量测量结果的测量不确定度主要来源于相对定量校正因子、检材量、检材中添加内标物叔丁醇的体积、检材中乙醇峰面积的平均值与添加内标物叔丁醇峰面积的平均值之比、无水乙醇的纯度及密度等参数引起的不确定度。当检材中乙醇的含量为0．915mg／mL时,扩展不确定度为O．030mg/mL(k=2)。     

Speech dereverberation method based on spectral subtraction and spectral line enhancement

Speech signals recorded with a distant microphone usually are interfered by the spatial reverberation in the room, which severely degrades the clarity and intelligibility of speech. A speech dereverberation method based on spectral subtraction and spectral line enhancement is proposed in this paper. Following the generalized statistical reverberation model, the power spectrum of late reverberation is estimated and removed from the reverberation speech by the spectral subtraction method. Then, according to the human auditory model, a spectral line enhancement technique based on adaptive post-filtering is adopted to further eliminate the reverberant components between adjacent speech formants. The proposed method can effectively suppress the spatial reverberation and improve the auditory perception of speech. The subjective and objective evaluation results reveal that the perceptual quality of speech is greatly improved by the proposed method.     

高灵敏可见／紫外条纹相机的最小可探测能量密度

分析了影响条纹相机最小可探测能量密度的主要因素，通过采用两级增强器级联的方法降低了条纹最小可探测能量密度。利用超短激光脉冲经过标准具后形成一个能量等比衰减的脉冲序列，对ＺＰＴ－３Ｋ紫外／可见皮秒条纹相机的最小可探测能量密度进行了测量。测量表明：相机最小可探测能量密度在可见波段（５３２ｎｍ）达１×１０－１３Ｊ／ｃｍ２。     

A graphene-based Au(111) platform for electrochemical biosensing based catalytic recycling of products on gold nanoflowers

A novel, enzyme-free amperometric immunoassay of biomarkers with sensitive enhancement was designed by using gold nanoflower-labeled detection antibodies toward the catalytic reduction of p-nitrophenol and redox cycling of p-aminophenol on a graphene-based Au(111) platform.     

Measurements of single-molecule electromechanical properties

The electromechanical properties of a single molecule covalently attached to two gold electrodes are studied by simultaneously measuring the conductance and the force during the stretching of the molecule. The conductance, the spring constant of the molecular junction, and the dependence of the conductance on the stretching force are determined. Like the conductance, the spring constant of a molecule depends also on the molecule-electrode contacts. The forces required to break the molecule-gold contacts are 1.5 nN for alkanedithiols and 0.8 nN for 4,4' bipyridine, indicating that the breakdowns take place at the Au-Au bond and at the N-Au bond, respectively.     

Sensitive detection of hydrogen peroxide in foodstuff using an organic�Cinorganic hybrid multilayer-functionalized graphene biosensing platform

We report on a new electrochemical biosensing strategy for the sensitive detection of hydrogen peroxide (H₂O₂) in foodstuff samples. It is based on a gold electrode modified with layer of graphene patterned with a multilayer made from an organic?Cinorganic hybrid nanomaterial. Initially, a layer of thionine (Th) was assembled on the surface of the graphene nanosheets, and these were then cast on the surface of the electrode for the alternate assembly of gold nanoparticles and horseradish peroxidase. The large surface-to-volume ratio and high conductivity of the nanosheets provides a benign microenvironment for the construction of the biosensor. The use of such a multilayer not only shortens the electron transfer pathway of the active center of the enzyme due to the presence of gold nanoparticles, but also enhances the electrocatalytic efficiency of the biosensor toward the reduction of H₂O₂. The electrochemical characteristics of the biosensor were studied by cyclic voltammetry and chronoamperometry. The number of layers, the operating potential, and the pH of the supporting electrolyte were optimized. Linear response is obtained for the range from 0.5???M to 1.8?mM of H₂O₂, the detection limit is 10 nM (at S/N?=?3), and 95% of the steady-state current is reached within 2?s. The method was applied to sense H₂O₂ in spiked sterilized milk and correlated excellently with the permanganate titration method.

基于SiPM读出的塑料闪烁体探测器时间性能研究

研究了基于硅光电倍增管(SiPM)双端读出的面积为10 cm ×10 cm的薄塑料闪烁体探测器的时间性能。239Pu放射源测试结果显示:(1)在多支SiPM串连读出方式下，随着SiPM数量的增加，探测器时间分辨逐渐变好；(2)在固定12支SiPM数量不变的情况下，并联支路越多，探测器时间分辨越差；(3)采用快时间塑料闪烁体并增加其厚度，可有效提高探测器时间分辨；(4)采用比束斑尺寸更大的塑料闪烁体，可有效提高探测器时间分辨的位置均匀性；(5)对于1 mm厚的EJ232塑料闪烁体探测器，在单端12支SiPM串行连接的情况下，可获得好于131 ps的时间分辨。这一研究对RIBLL2起始时间探测器的升级改造具有重要的指导意义。     

High Performance Bifunctional Electrocatalysts Designed Based on Transition-Metal Sulfides for Rechargeable Zn–Air Batteries

Due to the energy crisis by the excessive consumption of fossil fuels, Zinc–air batteries (ZABs) with high theoretical energy density have attracted people‘s attention. The overall performance of ZABs is largely determined by the air cathode catalyst. Therefore, it is necessary to develop high-efficiency and low-cost bifunctional catalysts to replace noble metal catalysts to promote the development of ZABs. Among a variety of cathode catalysts, TMS has become a research hotspot in recent years because of its better electrical conductivity than metal phosphides and metal oxides. In this work, we focus on the means of improving the electrocatalytic performance of transition-metal sulfides (TMS) providing ideas for us to rationally design high-performance catalysts. Furthermore, the performance improvement law between catalyst performance and ZABs is also discussed in this work. Finally, some challenges and opportunities faced in the research of TMS electrocatalysis are briefly proposed, and strategies for improving the performance of ZABs are prospected.