Optimization and performance evaluation of a fluorescent sensor for residual sulfonamide antibiotics in honey samples

In the quest to address the mounting concerns over sulfonamide antibiotic residues in food, which pose significant threats to public health and food safety, this study introduces a cutting-edge detection method. Surface molecular imprinting on silicon nanoparticles is harnessed to fabricate a novel fluorescent sensor that exploits the luminescent properties of cadmium telluride (CdTe) quantum dots. This innovative approach aims to detect residual sulfonamide antibiotics with high specificity and sensitivity. At the heart of this research is the development of a core-shell nanostructure, where silicon dioxide serves as the core, and a molecularly imprinted polymers (MIPs) layer, tailored to recognize sulfamethazine (SM₂), forms the shell. The pivotal advancement in this sensor design is the integration of highly fluorescent CdTe quantum dots within the MIPs layer, which significantly enhances the signal response, enabling the detection of SM₂ with remarkable precision. The synthesis of this sensor employs a novel strategy, utilizing 3-aminopropyltriethoxysilane as the functional monomer, while tetraethyl orthosilicate and ammonium hydroxide act as catalysts to facilitate the polymerization reaction. This meticulous process yields a stable core-shell structure with active fluorescent properties. Experimental results reveal that under optimal conditions, the sensor exhibits a robust linear response to SM₂ concentrations ranging from 10 to 60 μmol L⁻¹, with a detection limit as low as 0.78 μmol L⁻¹. Furthermore, when applied to real food samples, such as honey, the sensor not only demonstrates high recovery rates of 92.3%–98.1%, but also maintains a low relative standard deviation of less than 2.5%. The implications of this study are far-reaching, offering a promising avenue for the rapid and reliable monitoring of antibiotic residues in the food supply chain, thereby safeguarding consumer health and upholding food safety standards.     

聚（丙烯酸—丙烯酰胺）—碱金属盐复合物的合成与表征

作为功能材料的一个新品种,高分子固体电解质有极其广泛的应用前景[1]。近年来人们致力于对体系的改性研究[2-5],以提高电解质的室温离子电导率和获得适合的力学性能。本研究用水溶液聚合工艺,以过硫酸盐为引发剂,以丙烯酸为主单体、丙烯酰胺为第二单体,加入适当的增塑剂...     

THE OCCUPATION DENSITY FIELD FOR THE CATALYTIC SUPER-BROWNIAN MOTION

61.IntroductionLetW=[w,,ll.,.,s,t2o,aER']denoteastandardBrownianmotioninRdwithsendgroup{Pt,t2o},C(R')denotetheBanachspaceofcontinuousboundedfunctionsonRdequlppedwiththesupnorm.rk.(a):=(1 Ial')-p/',aERd,Cr(R'):-{feC(R'),lf(x)l5CIof.(x)}withsomeconstantCj,Mv(R'):={pisffedonmeasureonRdandJ(1 lxlp)-'p(dx)d.(P,i):=ff(x)p(dx),AisLebesgUemeasure.GiventheordinaryMP-valuedsuper-Brownianmotiono:=[o,,fl1,Ps,#,t2s2O,pEMP]asthecatalyticmedium,Dawsona…     

参数激励下静电驱动微机电系统动力特性研究

充分考虑压膜阻尼效应的影响,提出参数激励下时变电容式静电驱动微机电系统的动力学模型,采用谐波平衡法分析在参数激励和强迫激励耦合作用下系统的幅频响应特性,探讨不同控制电压和频率比对系统幅频响应的影响,分别以交流电压幅值、频率比和压膜阻尼比为控制参数研究系统的非线性动力特性,结果表明,微尺度下静电驱动微机电系统在参数激励作用下存在较为丰富的分岔与混沌行为,压膜阻尼效应对系统动力特性的影响不可忽视.      

火焰原子吸收光谱法连续测定茶叶中的锌、铜和锰

本文研究了茶叶中锌、铜、锰微量金属元素的火焰原子吸收分光光度法的测定。方法简便、快速,灵敏度和精密度高,特征浓度锌为０．００９μｇ／ｍＬ／１％,铜为０．０３１μｇ／ｍＬ／１％,锰为０．０１７μｇ／ｍＬ／１％;相对标准偏差为０．９％～５．０％,回收率９２．０％～１０６．０％。     

投影算子组的联合谱

本文研究Hilbert空间H上投影算子组的联合谱.首先通过计算给出正则投影对的联合谱,进而给出一般的投影算子对的联合谱.本文还对两个投影算子的和与差的可逆性给出一些等价刻画.特别地,当P和Q为正则投影对时,本文通过计算算子组[I,P,Q]的联合谱来给出σ(P+Q)和σ(P-Q)的具体刻画.反过来,本文证明两类具有特定形...     

溶胶-凝胶法制备Ce3+掺杂纳米SiO2材料光致发光研究

通过溶胶-凝胶技术制备了掺杂Ce^3＋离子的纳米SiO2材料,并经较低温度下煅烧,研究其光致发光（PL）性能。X射线衍射（XRD）及透射电子显微镜（TEM）测试结果表明该纳米材料具有非晶态结构,颗粒尺寸为20～30nm。对其光致发光谱的测定显示：经450℃低温煅烧,未掺杂SiO2样品的光致发光谱明显为多峰的宽带结构,而微量Ce^3＋掺杂的样品在230nm激发下存在着唯一的一个很强的、主峰位于346nm左右的紫外发光峰,与未掺杂SiO2及Cu^2＋掺杂SiO2样品的比较表明该发光峰并非常见的Ce^3＋离子的d-f跃迁产生的特征发光带,而是起源于SiO2中的某种本征缺陷中心。通过不同煅烧温度以及不同Ce^3＋离子掺杂量对346nm发光峰强度的影响,讨论该发光峰起源可能的结构模型。     

Ultraconvergence of the derivative of high-order finite element method for elliptic problems with constant coefficients

In this article, for second order elliptic problems with constant coefficients, the local ultraconvergence of the derivative of finite element method using piecewise polynomials of degrees k (k ≥ 2) is studied by the interpolation postprocessing technique. Under suitable regularity and mesh conditions, we prove that at an interior vertex, which is away from the boundary with a fixed distance, the gradient of the postprecessed finite element solution using piecewise polynomials of degrees k (k ≥ 2) converges to the gradient of the exact solution with order . Numerical experiments are used to illustrate our theoretical findings.