检索结果-南通市图书馆

Bio-screening and quantification of methyl paraben in vinegar and coconut juice separated by HPTLC

在线全文

学校读者我要写书评

暂无评论

Food Science and Human Wellness 2024年第3期13卷 1602-1607页

作者： Yisheng Chen xingjun xi College of Food Science and Engineering Shanxi Agricultural UniversityTaigu 030801China Insitute of Food Nutrition and Safety Shanxi Agricultural UniversityTaiyuan 030031China Institute of Agricultural Food Standardization China National Institute of StandardizationBeijing 100191China

As a widely used food preservative,methyl paraben was experimentally evidenced with serious hormonelike adverse ***,a high performance thin-layer chromatography platformed bioluminescent bioautography and image analysis for the selective quantification and confirmation of methyl paraben was proposed and validated in vinegar and coconut ***,the detectability of the bioautography to the analyte on different layer materials was estimated,revealing that normal silica gel was the best *** that,the liquid of sample extract and working solution were separated to overcome the background noises due to co-extracted *** separation result was then coupled to the optimized bioautography,enabling instant and straightforward screening of the targeted *** accurate quantification,bioluninescent inhibition pattern caused by the analyte was processed by image analysis,giving useful sensitivity(LOD>16 mg/kg),precision(RSD<10.1%)and accuracy(spike-recovery rate 76.9%-112.2%).Finally,the suspected result was confirmed by determining its MS fingerprint,further strengthening the reliability of screening.

关键词： High performance thin-layer chromatography Bio-screening Bioluminescence Image analysis Methyl paraben

Parameter Estimation of Sub-/Super-synchronous Oscillation Based on Interpolated All-phase Fast Fourier Transform with Optimized Window Function

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1031-1041页

作者： Bo Sun xi Wu xi Chen Zixiao Zou Qiang Li Bixing Ren School of Electrical Engineering Southeast UniversityNanjingChina State Grid Jiangsu Electric Power Company Limited Research Institute NanjingChina

In recent years,with increasing amounts of renew-able energy sources connecting to power grids,sub-/super-syn-chronous oscillations(SSOs)occurred more *** to the time-variant nature of SsO magnitudes and frequencies,as well as the mutual interferences among SsO modes with close frequencies,the accurate parameter estimation of SsO has be-come a particularly challenging *** solve this issue,this paper proposes an improved spectrum analysis method by im-proving the window function and a spectrum correction method to achieve higher ***,by aiming at the sidelobe characteristics of the window function as evaluation criteria,a combined cosine function is optimized using a genetic algorithm(GA).Furthermore,the obtained window function is self-con-volved to extend its excellent characteristics,which have better performance in reducing mutual interference from other SSO ***,a new form of interpolated all-phase fast Fourier transform(IpApFFT)using the optimized window func-tion is proposed to estimate the parameters of *** meth-od allows for phase-unbiased estimation while maintaining algo-rithmic simplicity and *** performance of the pro-posed method is demonstrated under various conditions,com-pared with other estimation *** results vali-date the effectiveness and superiority of the proposed method.

关键词： Sub-/Super-synchronous oscillation(SSO) window function parameter estimation interpolated all-phase fast Fourier transform(ApFFT)

Synthesis and properties of nickel borate acylate as a new rubber-steel cord adhesion promoter

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Central South University of Technology 2001年第4期8卷 244-248页

作者： LI xiao ru 1,NIE xi du 2,WU Hai ying 1,CHENG Ben cheng 1 (1 College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China 2 Hengyang Branch of Hunan University, Hengyang 412000, China) College of Chemistry and Chemical Engineering Central South University Changsha China Hengyang Branch of Hunan University Hengyang China

The synthetic method of nickel borate acylate (NBA), a kind of rubber steel cord adhesion promoter (AP), through nickel carbonate, borate and mixed carboxylic acid was studied. The preparation of nickel carbonate could be performed through reaction of nickel sulfate with sodium carbonate in aqueous solution, in which fractional conversion of nickel was more than 99.9%. The mixed nickel carboxylate was prepared by the reaction of nickel carbonate with isooctanoic acid and acetic acid, under strong stirring for 2 h, the mole ratio of these chemicals were 1∶1∶1.1 respectively, and water should be removed completely by adding of inert organic solvent after reaction was finished so as to avoid hydrolysis of tributyl borate in the second reaction. NBA was synthesized by reaction of mixed nickel carboxylate with tributyl borate under strong stirring at 200 250 ℃ for 6 h. By detection and comparison with 680C product from Manobond Company of England, the NBA synthesized through isooctanoic acid and tributyl borate was very similar to product 680C in IR data, 300% fixed extension strength, tensile strength, hardness and cure curve, and was slightly lower than those of product 680C in tensile failure extensibility and hot air aging. The experimental results show that the prepared NBA can be used as rubber steel cord AP.

关键词： nickel borate acylate adhesion promoter nickel carbonate borate

中华蝈螽与中华螽斯精子超微结构研究(直翅目,螽斯总科)

在线全文

学校读者我要写书评

暂无评论

动物分类学报 2005年第3期30卷 461-466页

作者：杜喜翠石福明西南农业大学植保学院重庆400716 河北大学生命科学院保定071002

研究了中华蝈螽Gampsocleissinensis与中华螽斯Tettigoniachinensis精子的超微结构。两种精子的顶体复合体侧生于核上且包裹了核的一部分,顶体复合体横切面两侧角分离或两侧角与细胞核远离,或仅见其一侧角;中华蝈螽顶体外层在顶体本体... 详细信息

研究了中华蝈螽Gampsocleissinensis与中华螽斯Tettigoniachinensis精子的超微结构。两种精子的顶体复合体侧生于核上且包裹了核的一部分,顶体复合体横切面两侧角分离或两侧角与细胞核远离,或仅见其一侧角;中华蝈螽顶体外层在顶体本体两侧角外多呈晕圈状;轴丝为典型的9+9+2型;轴丝两侧的副纤维结构为2副微管;轴丝与线粒体衍生体之间的连接带3条;中华蝈螽有的横切面中两扁平膜池连接在一起;两种精子的中心粒侧体部位具五纵层细胞器。

关键词：螽斯科中华蝈螽中华螽斯精子超微结构

An extended numerical model of the first exothermic peak for three dimensional printed cement-based materials

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2024年第1期18卷 80-88页

作者： Wei JIANG Wenqian LI xi CHEN School of Materials Science and Engineering Tongji UniversityShanghai 200092China School of Civil Engineering Tongji UniversityShanghai 200092China

The first exothermic peak of cement-based material occurs a few minutes after mixing,and the properties of three dimensional(3D)printed concrete,such as setting time,are very sensitive to *** this background,based on the classical Park cement exothermic model of hydration,we propose and construct a numerical model of the first exothermic peak,taking into account the proportions of C_(3)S,C_(3)A and quicklime in *** calculated parameters are calibrated by means of relevant published exothermic test *** is found that this developed model offers a good simulation of the first exothermic peak of hydration for C_(3)S and C_(3)A proportions from 0 to 100% of cement clinker and reflects the effect of quicklime content at 8%-10%.The unique value of this research is provision of an important computational tool for applications that are sensitive to the first exothermic peak of hydration,such as 3D printing.

关键词： 3D printed cement-based materials cement hydration the first exothermic peak liquid quick-setting agent numerical model

A new method to solve the Reynolds equation including mass-conserving cavitation by physics informed neural networks(PINNs)with both soft and hard constraints

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第6期12卷 1165-1175页

作者： Yinhu xi Jinhui DENG Yiling LI School of Mechanical Engineering Anhui University of Science and TechnologyHuainan 232001China Ericsson AB Datalinjen 3Linköping 58330Sweden

In this work,a new method to solve the Reynolds equation including mass-conserving cavitation by using the physics informed neural networks(PINNs)is *** complementarity relationship between the pressure and the void fraction is *** are several difficulties in problem solving,and the solutions are ***,the difficulty for considering the pressure inequality constraint by PINNs is solved by transferring it into one equality constraint without introducing *** the void fraction inequality constraint is considered by using the hard constraint with the max-min ***,to avoid the fluctuation of the boundary value problems,the hard constraint method is also utilized to apply the boundary pressure values and the corresponding functions are ***,for avoiding the trivial solution the limitation for the mean value of the void fraction is *** results are validated against existing data,and both the incompressible and compressible lubricant are *** agreement can be found for both the domain and domain boundaries.

关键词： Reynolds equation mass-conserving cavitation physics informed neural networks hard constraints trivial solution

修正的氢谱指数与白柠檬香气成分理化性质的定量关系

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

食品科学 2009年第22期30卷 301-304页

作者：堵锡华陈艳徐州工程学院化学化工学院江苏徐州221008

为研究白柠檬精油的特征香气成分,定义并修正了原子的特征值δi,利用分子图形学技术获得了氢谱指数mH,基于多元回归方法建立能估算和预测白柠檬精油香气成分保留指数和香气值的定量结构-性质相关性模型,得到多元回归方程,回归方程相关系... 详细信息

为研究白柠檬精油的特征香气成分,定义并修正了原子的特征值δi,利用分子图形学技术获得了氢谱指数mH,基于多元回归方法建立能估算和预测白柠檬精油香气成分保留指数和香气值的定量结构-性质相关性模型,得到多元回归方程,回归方程相关系数r分别为0.949和0.847,估算保留指数的平均相对误差为3.55%。结果表明,指数与保留指数RI和香气值Uo之间有较好的线性关系,模型能较好地解释精油香气成分保留指数和香气值的递变规律。利用Jackknifed法检验模型的稳定性和预测能力,Jackknifed检验的相关系数均在0.94以上。

关键词：白柠檬香气成分气相色谱保留指数氢谱指数定量结构-性质相关性(QSPR)

在线全文

学校读者我要写书评

暂无评论

柚子皮香精油挥发性成分的保留相关性研究

食品科学 2009年第19期30卷 61-64页

作者：堵锡华陈艳徐州工程学院化学化工学院江苏徐州221008

为研究柚子皮香精油挥发性组分的保留性质和香气特征,利用拓扑指数建立了能估算和预测香精油挥发性组分保留指数的定量结构-保留相关性模型,经逐步回归筛选变量后,所建多元线性回归方程相关系数(r)为0.940,估算的平均相对误差为3.53%。... 详细信息

为研究柚子皮香精油挥发性组分的保留性质和香气特征,利用拓扑指数建立了能估算和预测香精油挥发性组分保留指数的定量结构-保留相关性模型,经逐步回归筛选变量后,所建多元线性回归方程相关系数(r)为0.940,估算的平均相对误差为3.53%。用多元回归方法构建的对香精油挥发性组分香气值进行估算的定量结构-性质相关模型,相关系数能达到0.702,结果表明,它们之间有较好的线性关系,模型能较好地解释香精油挥发性组分保留指数和香气值性质的递变规律。

关键词：柚子挥发性成分香气值气相色谱保留指数拓扑指数定量结构-保留相关性

在线全文

学校读者我要写书评

暂无评论

薄荷挥发性成分的定量结构-性质相关性

食品科学 2013年第6期34卷 192-194页

作者：堵锡华陈艳徐州工程学院化学化工学院江苏徐州221111

预测薄荷挥发性分子的保留指数和准确质量,以利用它们对分子进行有效的定性。在分子拓扑理论的基础上,应用AM1法得到65种薄荷挥发性成分的优势构象,计算得到Kier指数和E-State指数,基于多元回归分析获得了对薄荷挥发性成分的保留指数(RI... 详细信息

预测薄荷挥发性分子的保留指数和准确质量,以利用它们对分子进行有效的定性。在分子拓扑理论的基础上,应用AM1法得到65种薄荷挥发性成分的优势构象,计算得到Kier指数和E-State指数,基于多元回归分析获得了对薄荷挥发性成分的保留指数(RI)和准确质量(M)作出精确预测的定量结构-保留相关性模型。回归方程的相关系数分别为0.986和0.998。利用Jackknifed法检验了对保留指数预测模型的稳定性,检验的相关系数r基本也为0.986;另外对准确质量预测模型的稳定性和预测能力进行检测,预测值与实验值的相对平均误差为1.43%。两个模型均具有较好的稳定性、相关度和预测能力。

关键词：拓扑指数保留指数薄荷挥发性成分定量结构-性质相关性