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Bi-large Neutrino Mixing See-Saw Mass Matrix with Texture Zeros and Leptogenesis
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作者 CHAO Wei HE Xiao-Gang LI Xue-Qian 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第6期1073-1084,共12页
我们与质地零并且与相关迪拉克中微子团矩阵为双性人大的 mixingSee 锯团矩阵的一个班在中微子性质上学习限制与形式 diag 的一个斜矩阵成正比(ε, 1, 1 ) 。质地零可以发生在光(班一)) 或在里面重(班 b )) 中微子团矩阵。每这二个班... 我们与质地零并且与相关迪拉克中微子团矩阵为双性人大的 mixingSee 锯团矩阵的一个班在中微子性质上学习限制与形式 diag 的一个斜矩阵成正比(ε, 1, 1 ) 。质地零可以发生在光(班一)) 或在里面重(班 b )) 中微子团矩阵。每这二个班有能生产的 5different 形式重要与至少一块质地混合的三代零。我们在 and 班 b 能是的两个班上发现那质地零集体矩阵的二种类型与中微子群众上的现在的数据一致、混合。任何一个都不能中微子有零群众,轻中微子的最轻为班有比大约 0.046 eV 大的一个团为班 b 的 and0.0027 eV。尽管违背阶段的 CKM CP 消失,在这些模型, non-zeroMajorana 阶段能存在并且能在生产观察酒吧起一个重要作用在我们通过 leptogenesis 的宇宙的那里的不对称现象机制。生产观察 baryonasymmetry 的要求能进一步区分不同模型并且也限制跷跷板规模在 10 ~(12 ) 的范围~ 10 ~(15 ) GeV。我们也在 V_(13 ) 上讨论 RG 效果。 展开更多
关键词 微中子 质量矩阵 混合矩阵 中子物理学
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An Upper Bound on the Higgs Self-Coupling and Higgs Boson Mass from the Positivity Condition of the Mass Matrix
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作者 Partha Pratim Pal 《Journal of Modern Physics》 2015年第4期369-373,共5页
The actual value of Higgs boson mass is difficult to determine theoretically due to lack of knowledge on the exact value of Higgs self coupling constant l. The purpose of this paper is to obtain an upper bound on the ... The actual value of Higgs boson mass is difficult to determine theoretically due to lack of knowledge on the exact value of Higgs self coupling constant l. The purpose of this paper is to obtain an upper bound on the Higgs mass in the Standard Model on the basis of one-loop effective potential in the ’t Hooft-Landau gauge and MS scheme. The condition of positivity of mass matrix at ф?= ф0 (where ф0 is the absolute minimum of the effective potential) of the scalar field gives an upper bound on the Higgs self coupling as l ≤ 0.881. This condition yields an upper bound on the Higgs mass as mH ≤ 229.48 GeV. 展开更多
关键词 ONE-LOOP Effective Potential Standard Model mass matrix HIGGS BOSON mass
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The Majorana neutrino mass matrix indicated by the current data
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作者 ZHANG XinYi MA BoQiang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2015年第7期36-48,共13页
The Majorana neutrino mass matrix combines information from the neutrino masses and the leptonic mixing in the flavor basis. Its invariance under some transformation matrices indicates the existence of certain residua... The Majorana neutrino mass matrix combines information from the neutrino masses and the leptonic mixing in the flavor basis. Its invariance under some transformation matrices indicates the existence of certain residual symmetry. We offer an intuitive display of the structure of the Majorana neutrino mass matrix, using the whole set of the oscillation data. The structure is revealed depending on the lightest neutrino mass. We find that there are three regions with distinct characteristics of structure. A group effect and the-τ exchange symmetry are observed. Six types of texture non-zeros are shown. Implications for flavor models are discussed. 展开更多
关键词 中微子质量 质量矩阵 当前数据 交换对称性 变换矩阵 群体效应 结构 风味
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ELASTO-PLASTIC STIFFNESS MATRIX OF ROCK MASS ELEMENT WITH SOFT CLAY STRATA AND ITS APPLICATION
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作者 Li,Zhenzi Sun,Zongqi Central-South University of Technology,Changsha,Hunan,410083,China 《中国有色金属学会会刊:英文版》 CSCD 1993年第2期15-17,共3页
The fault element is used to handle soft clay strata in a rock mass.The formulas or clasto-plastic stiffnessmatrix for the fault element are derived using the constitutive relationship between plastic increment stress... The fault element is used to handle soft clay strata in a rock mass.The formulas or clasto-plastic stiffnessmatrix for the fault element are derived using the constitutive relationship between plastic increment stress andstrain.A numerical example of a circular tunnel with soft clay strata in the rock medium are examined. 展开更多
关键词 rock mass clement FAULT clasto-plastic STIFFNESS matrix
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用于夹层梁静动力及屈曲分析的新型组合结构单元
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作者 林建平 陈昆 +2 位作者 潘剑超 王冠楠 冯倩 《浙江大学学报(工学版)》 EI CAS CSCD 北大核心 2024年第3期518-528,共11页
推导出新型组合结构单元,用于考虑界面滑移的3层部分作用夹层组合梁的静动力及屈曲特性分析.基于铁木辛柯梁理论,建立考虑夹层梁部分作用效应的能量原理.针对其受力特性,在节点位移、横截面转角和界面滑移插值时均采用含内部自由度的高... 推导出新型组合结构单元,用于考虑界面滑移的3层部分作用夹层组合梁的静动力及屈曲特性分析.基于铁木辛柯梁理论,建立考虑夹层梁部分作用效应的能量原理.针对其受力特性,在节点位移、横截面转角和界面滑移插值时均采用含内部自由度的高阶插值函数,以解决含界面有限元数值分析中常遇到的“滑移锁定”现象.通过变分原理得到夹层梁的刚度矩阵、质量矩阵以及几何刚度矩阵的显示表达式.基于MATLAB编译相应夹层结构的有限元程序并验证其准确性.对不同截面3层夹层组合梁进行不同荷载条件和边界条件下的静动力及屈曲特性分析,并探讨不同夹层组合梁跨高比和不同界面抗剪连接刚度下的计算结果及其误差的变化规律.所推导的显示表达式新型组合结构单元计算效率高,并便于推广应用于其他有限元程序或商业软件子程序中. 展开更多
关键词 夹层组合梁 部分作用 静动力分析 刚度矩阵 质量矩阵 铁木辛柯梁理论
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埃尔米特梁单元的分块对角与高阶质量矩阵
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作者 王东东 吴振宇 侯松阳 《计算力学学报》 CAS CSCD 北大核心 2024年第1期178-185,共8页
埃尔米特梁单元常用的集中质量矩阵,是由挠度自由度对应的一致质量矩阵元素通过行求和或节点积分构造.然而,数值结果表明该集中质量矩阵在求解包含自由端的梁振动问题时,会出现频率精度掉阶现象.本文首先从保障质量矩阵最优收敛性的数... 埃尔米特梁单元常用的集中质量矩阵,是由挠度自由度对应的一致质量矩阵元素通过行求和或节点积分构造.然而,数值结果表明该集中质量矩阵在求解包含自由端的梁振动问题时,会出现频率精度掉阶现象.本文首先从保障质量矩阵最优收敛性的数值积分精度出发,分别针对三次和五次梁单元,发展了质量矩阵的梯度增强节点积分方案.利用梯度增强节点积分方案,可以得到具有分块对角形式的单元质量矩阵,而其组装的整体质量矩阵除边界节点外仍然呈现对角形式.对于两种单元,其分块对角质量矩阵分别具有4阶最优精度和6阶次优精度.再者,将标准一致质量矩阵和具有同阶精度的梯度增强节点积分质量矩阵进行优化组合,建立了具有超收敛特性的高阶质量矩阵.最后,通过数值算例系统验证了三次和五次单元的分块对角与高阶质量矩阵的频率计算精度. 展开更多
关键词 埃尔米特梁单元 振动频率 集中质量矩阵 分块对角质量矩阵 高阶质量矩阵
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UHAS-MIDA Software Package: Mass Isotopomer Distribution Analysis-Applying the Inverse Matrix for the Determination of Stable Isotopes of Chromium Distribution during Red Blood Cell Labelling
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作者 Daniel A. Abaye Emmanuel B. Odoom +3 位作者 Ernest Y. Boateng Irene A. Agbo John-Bosco Diekuu Samuel Agana 《Journal of Data Analysis and Information Processing》 2022年第2期142-154,共13页
Clinical assessment of fluid volume status in children during malaria can be taxing and often inaccurate. During malaria, changes in fluid volume are rather multifarious and estimating this parameter, especially in si... Clinical assessment of fluid volume status in children during malaria can be taxing and often inaccurate. During malaria, changes in fluid volume are rather multifarious and estimating this parameter, especially in sick children is very challenging for clinicians who frequently rely on indices such as long capillary refill times, tachycardia, central venous pressure and decreased urine volume as guides. Here, we present the UHAS-MIDA, an open-source software tool that calculates the red blood cell (RBC) concentration and blood volume during malaria in children determined using a stable isotope of chromium (<sup>53</sup>Cr as the label) by gas chromatography-mass spectrometry in selective ion monitoring (GC/MS-SIM) analysis. A key component involves the determination of the compositions of the most abundant naturally occurring isotopes of Cr (<sup>50</sup>Cr, <sup>52</sup>Cr, <sup>53</sup>Cr), and converting the proportions into a 3 × 3 matrix. To estimate unknown proportions of chromium isotopic mixtures from the measured abundances of three ions, an inverse matrix was calculated. The inverse together with several inputs is then used to calculate the corrected MS ion abundances. Thus, we constructed the software tool UHAS- MIDA using HTML, CSS/Bootstrap, JavaScript, and PHP scripting languages. The tool enables the user to efficiently determine RBC concentration and fluid volume. The source code, binary packages and associated materials for UHAS-MIDA are freely available at https://github.com/bentil078/Abaye-et-al_UHASmida 展开更多
关键词 mass Isotopomer Distribution Analysis Inverse matrix GC/MS Chromium Stable Isotopes Blood Volume Red Blood Cell mass
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Effect of Sample Matrix on Radial and Axial Profiles of Ion Abundance in Inductively Coupled Plasma Mass Spectrometry
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作者 Clarisse Mariet Francine Carrot Mélanie Moskura 《American Journal of Analytical Chemistry》 2011年第7期739-751,共13页
In inductively coupled plasma mass spectrometry (ICP-MS) analysis, only a few options are available to deal with non-spectroscopic interferences. Considering that diluting the sample is impractical for traces analysis... In inductively coupled plasma mass spectrometry (ICP-MS) analysis, only a few options are available to deal with non-spectroscopic interferences. Considering that diluting the sample is impractical for traces analysis, other alternatives must be employed. Traditionally, the method of standard additions is used to correct the matrix effect but it is a time consuming method. Others methods involves separation techniques. Another way to overcome matrix interferences is to understand the mechanism involved and adjust plasma viewing conditions to reduce or eliminate the effect. In this study, the effect of various concomitant elements in ICP-MS was assessed by measuring the distribution of selected singly charged analyte ions (Al, V, Cr, Mn, Ni, Co, Cu, Zn, As, In, Ba, La, Ce, Pb), doubly charged ions (La, Ce, Ba and Pb) and oxides ions (BaO) in the presence of concomitant elements spanning a mass range from 23 (Na) to 133 (Cs) u.m.a. and different ionization energies. Concomitant elements are alkali metals, alkaline earth metals and Si. Analyte ion suppression was observed while moving the ICP across and away from the sampling interface with or without a single concomitant element. Matrix effect measures were realised, firstly, to highlight the relation between the signal extinction of an analyte and the masse of the concomitant element, and secondly to highlight the relation between the removal of the analyte signal and the first ionization energy of the element of matrix. A dependence upon both the mass of the matrix element and the mass of the analyte was observed. The suppression seems increased with increasing matrix element mass and decreased with increasing analyte mass. The effect of the mass of the matrix element was the more significant of the two factors. If space-charge effects were found to be significant for matrix elements of much lower mass, it seems diffusion also played an active part for heavier matrix elements. Finally, some evidence was found for a shift in ion-atom equilibrium for dications and for energy demand regarding oxides. 展开更多
关键词 matrix Effects Easily Ionized Elements Inductively Coupled Plasma mass SPECTROMETRY Spatial PROFILING
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A novel sample preparation method of matrix-assisted laser desorption/ionization time of flight mass spectrometry for polystyrene
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作者 Shu Zhang Zhen Wen Zhao +3 位作者 Lei Xiong Bin Xin Wei Hua Hu Shao Xiang Xiong 《Chinese Chemical Letters》 SCIE CAS CSCD 2007年第6期718-721,共4页
关键词 POLYSTYRENE matrix-assisted laser desorption/ionization time of flight mass spectrometry Three-layer method
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New Kinetic Computerized Model for Multicomponent Mass Transfer in Bi-Functional Matrix of NanoComposites
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作者 Anatoliy Kalinitchev 《Advances in Nanoparticles》 2013年第2期191-203,共13页
The aim of this theoretical investigation is the description of the multicomponent mass transfer process in the Nano- Composites (NC)—novel materials with the bi-functional matrix. The new theoretical NC Model is ass... The aim of this theoretical investigation is the description of the multicomponent mass transfer process in the Nano- Composites (NC)—novel materials with the bi-functional matrix. The new theoretical NC Model is assigned for the modern theoretical investigations of the multicomponent mass transfer kinetics in the bi-functional NC materials. This NC Model for the multicomponent mass transfer in the bi-functional NC matrix includes into the consideration the proposed key conception—two co-existing routes: I—chemical reactions onto the active NC centers-sites, and II—diffusion mass transfer inside the bi-functional NC matrix. All the results are presented in the terms of the additional key concept: propagating multicomponent concentration waves (W+) in the NC matrix. The used W+ concept for the description of the multicomponent NC mass transfer kinetics give the clear interpretation of the computerized results. The mass transfer process in the NC matrix has been described theoretically by computerized simulation. The results of the calculations are new and illustrated by author’s animations showing visually the propagation of the multicomponent concentration waves (W) inside the various NC matrixes: r-beads, cylindrical ro-fibers, or planar L-membranes. Two variants of modeling for mass transfer diffusion kinetics in the bi-functional NC matrixes with one (Variant 1), or two (Variant 2) dissociation-association reactions at the active nano-sites (R0) are considered theoretically. 展开更多
关键词 NANOCOMPOSITES mass Transfer Concentration Waves Diffusion MULTICOMPONENT Kinetics Bi-Functional matrix Active Nano-Sites
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MicrobMatcher: a microbial comparison software based on matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry
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作者 Yizhen Fu Feng Liu Yalu Ye 《Journal of Biomedical Science and Engineering》 2011年第5期403-409,共7页
Matrix-assisted Laser Desorption/Ionization with Time-of-flight Mass Spectrometry (MALDI-TOFMS) was investigated as a method for the rapid identifica-tion of species. Current demand in microbial identi-fication is how... Matrix-assisted Laser Desorption/Ionization with Time-of-flight Mass Spectrometry (MALDI-TOFMS) was investigated as a method for the rapid identifica-tion of species. Current demand in microbial identi-fication is how to compare unknown strains to the known one quickly, semi-automatically and accurately. In this paper, we present a software tool that allows flexibly microbial matching in a user-friendly way, by letting the users to customize comparison parameters including: in vitro transcription enzyme, mass tolerance,minimum fragment length, intensity threshold and corresponding weights. We provide three spectral scoring functions to compute the affin-ity between the species. Therefore, the precision of microbial comparison increases. To test and verify this tool, we employed experimental spectral data based on MALDI-TOFMS and the gene sequences of E.coli and Salmonella. This software is written in Java for cross-platform intention. 展开更多
关键词 MICROBIAL Comparison matrix-Assisted Laser Desorption/Ionization with TIME-OF-FLIGHT mass SPECTROMETRY
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Analysis of Single Nucleotide Polymorphism in Human Paraoxonase 1 Gene(Q192R) with Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry
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作者 SUN Ya-dong SUN Shu-chen +2 位作者 WANG Zhi YANG Yang ZHANG Jin 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2006年第3期394-396,共3页
Introduction Single nucleotide polymorphisms (SNPs) are the most abundant DNA markers in the human genome occurring at a frequency of one in every 500--1000 nucleotides. A variety of methods have been used for the ... Introduction Single nucleotide polymorphisms (SNPs) are the most abundant DNA markers in the human genome occurring at a frequency of one in every 500--1000 nucleotides. A variety of methods have been used for the analysis of single nucleotide polymorphisms, including restriction fragment length polymorphism (RFLP), direct sequencing by using laser-induced fluorescence detectionTM, fluorescence energy transfer, MALDI-TOF MS combined with primer extension or invasive cleavage, and fluorescence polarization. During the past two decades, mass spectrometry has become a very popular tool in the analysis of biomolecules and is perfectly suited to the analysis of single nucleotide polymorphisms (SNPs) due to its speed, low cost, and accuracy. In this work, we used MALDI TOF mass spectrometry to detect the fragments of restriction endonuclease hydrolysis of PCR products flanking a SNP located at paraoxonase 1(Q192R). Compared with electrophoresis, this method requires less time of analysis and possess a higher accuracy. 展开更多
关键词 Single nucleotide polymorphism Human paraoxonase 1 gene matrix-assisted laser desorption/ionizationtime-of-flight mass spectrometry
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基于响应面法的基质固相分散萃取土壤中有机磷阻燃剂
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作者 王俊霞 徐思婕 +4 位作者 孙悦莹 雷慧慧 程媛媛 王学东 张占恩 《色谱》 CSCD 北大核心 2024年第1期64-74,共11页
有机磷阻燃剂(OPFRs)被广泛添加于商业品和日用品中,由于具有环境持久性、生物富集性和潜在毒性,已成为一种新兴的持久性有机污染物。因此需要建立能准确定量环境中OPFRs的检测方法。该文基于基质固相分散萃取(MSPD),结合气相色谱-串联... 有机磷阻燃剂(OPFRs)被广泛添加于商业品和日用品中,由于具有环境持久性、生物富集性和潜在毒性,已成为一种新兴的持久性有机污染物。因此需要建立能准确定量环境中OPFRs的检测方法。该文基于基质固相分散萃取(MSPD),结合气相色谱-串联质谱(GC-MS/MS)法测定土壤中10种有机磷阻燃剂,筛选对OPFRs具有高选择性的吸附剂,最终确定MSPD最佳萃取条件。该文基于单因素分析法考察了常见吸附剂(C18、PSA、Florisil、石墨化炭黑(GCB)和多壁碳纳米管(MWCNT))及其用量、洗脱溶剂及其体积、研磨时间对OPFRs萃取效率的影响。在此结果基础上,进一步利用响应面法(RSM)考察了3个关键因素(吸附剂用量、洗脱剂用量和研磨时间)以及交互作用对OPFRs萃取效率的影响。最终确定最优条件:吸附剂GCB,用量0.3 g;洗脱溶剂乙酸乙酯,用量10 mL;研磨时间5 min,此时10种OPFR的萃取效率为87.5%。在GC-MS/MS的多反应监测模式(MRM)下,以13C-PCB208为内标物进行定量。10种OPFRs在6个浓度梯度下,获得较好的线性,相关系数大于0.998。该方法的LOD和LOQ分别为0.006~0.161 ng/g和0.020~0.531 ng/g。在最佳条件下,加标土壤中OPFRs的加标回收率为70.4%~115.4%,相对标准偏差(RSD)为0.7%~6.7%。将该方法用于苏州不同功能土壤中OPFRs的含量测定,结果表明电子厂和汽修厂土壤中OPFRs总含量显著高于稻田土和校园土,电子厂和汽修厂土壤中主要污染物为磷酸三(2-氯异丙基)酯(TCIPP)、三苯基氧化膦(TPPO)、磷酸三(2-氯乙基)酯(TCEP)和磷酸三(1,3-二氯-2-丙基)酯(TDCPP),它们在电子厂土壤中含量分别为5.30、4.44、4.54、4.20 ng/g,在汽修厂土壤中的含量分别2.70、3.93、7.60、5.04 ng/g。目前关于TPPO的土壤污染报道较少,该研究在苏州工业区土壤中检出了高浓度TPPO污染。该方法成功用于土壤中10种OPFRs的检测。 展开更多
关键词 气相色谱-串联质谱 基质固相分散萃取 响应面法 有机磷阻燃剂 土壤
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Novel Approach for Quantitative Measurement of Matrix Metalloprotease-1 (MMP1) in Human Breast Cancer Cells Using Mass Spectrometry
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作者 Ming Fa Kathleen Hoch +3 位作者 Xuejun Fan William P. Dubinsky Zhiqiang An Ningyan Zhang 《Journal of Analytical Sciences, Methods and Instrumentation》 2013年第1期54-61,共8页
Identification and quantification of low abundance growth factors and regulators in complex biological samples still present a challenging task in analytical biochemistry. Immunoassays are often used for such purpose ... Identification and quantification of low abundance growth factors and regulators in complex biological samples still present a challenging task in analytical biochemistry. Immunoassays are often used for such purpose but immunoassays face limitation of both availability and qualities of antibody reagents that are necessary for development of immune assays. With genomics data base available, mass spectrometry (MS) can analyze protein tryptic peptides directly for quantitative determination of proteins. In this study, we report a method for detection of matrix metalloproteinase 1 (MMP1), an important extracellular matrix modulator, in human breast cancer cells by quadrupole time-of-flight (Q-TOF) MS. Absolute quantification of MMP1 was conducted using the selected reaction monitoring (SRM) on a triple quadrupole (Triple-Quad) MS via transitions selected from MMP1 tryptic peptides using non isotope labeled MMP1 protein as a titration standard. In comparison with immune based assay, this MS method showed picogram level sensitivity for quantitative determination of MMP1 intotal cell lysates. Our results demonstrated the feasibility of absolute quantification of low abundance proteins using label-free protein standard by mass spectrometry. Therefore, this method provides not only advantages of high sensitivity but also cost saving in comparison with the commonly used mass spectrometry that currently employs isotype labeled proteins for quantitative analysis. 展开更多
关键词 matrix Metalloprotease-1 (MMP1) SKBR3 BREAST Cancer Cells mass SPECTROMETRY Selected Reaction Monitoring ABSOLUTE Quantification
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H Control for Externally Excited Building Structures with Active Mass Damper under Actuator Saturation
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作者 Shulong Wei Yuanguang Zheng 《Open Journal of Applied Sciences》 2023年第11期1951-1966,共16页
This paper investigates the application of active mass dampers to mitigate the vibrations of building structures subjected to unknown external excitations under controller saturation conditions. By utilizing an H<s... This paper investigates the application of active mass dampers to mitigate the vibrations of building structures subjected to unknown external excitations under controller saturation conditions. By utilizing an H<sub>∞</sub> control strategy, the optimal state feedback controller is derived by solving the linear matrix inequality problem for controller saturation. Case studies show that the proposed controller is capable of stabilizing the closed-loop system with good control performance and effectively suppressing vibrations in building structures under unknown external excitation. When compared to controllers that do not consider saturation, the proposed controller requires lower gain and results in reduced energy consumption. The research findings provide valuable insights for addressing real-world building structure control problems, contributing to both theoretical significance and practical applications. 展开更多
关键词 Structural Vibration Active mass Damper H Control Controller Saturation Linear matrix Inequality
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胶州湾大气降水水溶性离子组成特征及来源解析
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作者 冯辰龙 邢建伟 +1 位作者 袁华茂 宋金明 《中国环境科学》 EI CAS CSCD 北大核心 2024年第3期1225-1233,共9页
基于2019年6月至2020年8月胶州湾沿岸的大气降水样品,分析降水主要水溶性离子(Na^(+)、K^(+)、Ca^(2+)、Mg^(2+)、NH^(4+)、F-、Cl^(-)、SO_(4)^(2-)、NO_(3)^(-)、MAS-(甲基磺酸根))的组成特征和湿沉降通量,评估其对近海营养成分输入... 基于2019年6月至2020年8月胶州湾沿岸的大气降水样品,分析降水主要水溶性离子(Na^(+)、K^(+)、Ca^(2+)、Mg^(2+)、NH^(4+)、F-、Cl^(-)、SO_(4)^(2-)、NO_(3)^(-)、MAS-(甲基磺酸根))的组成特征和湿沉降通量,评估其对近海营养成分输入的贡献和潜在生态效应,并利用气团后向轨迹和正定矩阵因子分解法(PMF)解析其主要来源.结果表明,观测期间,胶州湾大气降水雨量加权平均(Volume-weighted Mean,VWM)pH为6.41,电导率的VWM值为19.3μS/cm,降水中水溶性离子以Na^(+)、NH^(4+)、NO_(3)^(-)、Cl^(-)和SO_(4)^(2-)为主,在季节上呈现出冬春季浓度明显高于夏秋季的特征,而湿沉降通量则因受降水量的控制而主要集中在夏季(约占55%).胶州湾区域大气降水共清除7274.6t水溶性离子,营养盐(主要为NH^(4+)和NO_(3)^(-),以氮计)沉降入海量达951.9t/a,表明降水在清洁大气的同时也加剧了海洋环境的污染和海洋生态系统的失衡.气团后向轨迹分析得到了观测期间控制胶州湾降水的4类主要气团,在不同季节,降水过程受到不同气团的影响,其中以来自华东地区和东北方向的气团的影响较大.基于PMF的源解析结果显示,胶州湾大气降水水溶性离子受到农业源、海洋源、扬尘源、生物质和垃圾燃烧源、工业和交通源5种来源的共同控制,其中以农业源排放的贡献最为突出(26.7%),而其他4种源的贡献大致相当.研究证实胶州湾大气环境受到复杂人为源排放、矿物沙尘以及海洋源排放的综合制约,而人为排放的贡献占主导地位. 展开更多
关键词 水溶性离子 湿沉降通量 大气降水 气团后向轨迹 正定矩阵因子模型 胶州湾
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高盐食品基质中砷含量的测定
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作者 戴瑞平 刘花梅 +6 位作者 舒露 唐丽君 黎申英 李彪 张梅玲 刘涛 黄宗兰 《现代食品科技》 CAS 北大核心 2024年第4期321-330,共10页
建立了一种基体匹配-动态反应池-电感耦合等离子体质谱法测定高盐食品基质中砷含量的方法,以解决高盐基体对砷测定的质谱干扰和基体干扰。研究电感耦合等离子体质谱法与氢化物发生原子荧光光谱法测定食品中总砷的技术要点,通过分析前处... 建立了一种基体匹配-动态反应池-电感耦合等离子体质谱法测定高盐食品基质中砷含量的方法,以解决高盐基体对砷测定的质谱干扰和基体干扰。研究电感耦合等离子体质谱法与氢化物发生原子荧光光谱法测定食品中总砷的技术要点,通过分析前处理消解方式、有机基质、氯含量和内标校正元素等对砷含量测定的影响,建立了高盐食品基质中砷含量的测定方法。实验结果表明,微波消解法并不太适用于氢化物发生原子荧光光谱法测定食品中总砷,有机基质和氯分别会对砷的质谱测定信号产生增敏效应和质谱干扰,74Ge比72Ge更适合作为电感耦合等离子体质谱法测定食品中总砷的内标元素。建立的检测方法定量限0.010 mg/kg,高盐基体中砷在0.010、0.025、0.20、0.50 mg/kg添加水平的回收率为91.50%~110.80%,相对标准偏差范围为0.76%~7.22%。本法和参照法对样品分析结果统计值均大于t0.90,10(1.81,双边),测定结果存在显著性差异,对实际样品测定结果表明动能歧视测定模式并不太适用于高盐食品基质样品中总砷的测定。该方法准确可靠,能用于高盐和高基体食品中砷含量的测定分析。 展开更多
关键词 高盐食品基质 氢化物发生原子荧光光谱法 电感耦合等离子体质谱法 基体匹配
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磁性氮化碳复合材料的制备及其对磷酸化肽的富集
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作者 姜丽艳 张玮璐 +1 位作者 赵璐 胡良海 《色谱》 CAS CSCD 北大核心 2024年第6期564-571,共8页
蛋白质的磷酸化在细胞信号传导和疾病发生发展中起着重要作用,但磷酸化的动态变化和低丰度的特点使得对其直接分析有着较大的困难。为了解决磷酸化肽难离子化、检测丰度低的瓶颈问题,本研究制备了一种磁性氮化碳复合材料,结合基质辅助... 蛋白质的磷酸化在细胞信号传导和疾病发生发展中起着重要作用,但磷酸化的动态变化和低丰度的特点使得对其直接分析有着较大的困难。为了解决磷酸化肽难离子化、检测丰度低的瓶颈问题,本研究制备了一种磁性氮化碳复合材料,结合基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS),建立了一种对复杂样品中低丰度磷酸化肽富集与分析的方法。采用电子显微镜、红外光谱分析及X射线衍射分析等手段对合成的磁性氮化碳材料进行表征。以酪蛋白酶解产物为实验模型,发现磁性氮化碳材料能够实现对磷酸化肽的高选择性富集和高灵敏度检测,检出限为0.1 fmol。选择脱脂牛奶、人唾液和人血清为实际分析样品,发现磁性氮化碳材料对微量蛋白生物样品中磷酸化肽的分析具有较高的应用潜力。 展开更多
关键词 氮化碳 磁性固相萃取 基质辅助激光解吸电离飞行时间质谱 磷酸化肽 富集
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钻铬粘结相对碳化钨涂层磨粒磨损性能的影响
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作者 刘康生 胡水莲 谢道秀 《长沙航空职业技术学院学报》 2024年第2期1-4,43,共5页
采用超音速火焰喷涂(High-velocityOxygen-fuelSpraying,简称HVOF)工艺在30CrMnSiA基材表面制备了Co和CoCr粘结相质量分数分别为12%、14.5%和17%的三种WC复合涂层,研究了涂层显微组织结构、物相组成以及粘结相Co、Cr含量对WC涂层显微硬... 采用超音速火焰喷涂(High-velocityOxygen-fuelSpraying,简称HVOF)工艺在30CrMnSiA基材表面制备了Co和CoCr粘结相质量分数分别为12%、14.5%和17%的三种WC复合涂层,研究了涂层显微组织结构、物相组成以及粘结相Co、Cr含量对WC涂层显微硬度和耐磨粒磨损性能的影响,采用扫描电子显微镜观察涂层磨损前后的表面形貌,探讨了WC复合涂层的磨粒磨损机理。结果表明:超音速火焰喷涂WC复合涂层组织致密,涂层与基体结合良好,存在少量夹杂,涂层孔隙率均小于1%,涂层存在少量氧化物;粉末材料在喷涂过程中存在氧化和分解脱碳,生成了少量WC和Co,W,C两种脆性相,含Cr的涂层中发现了少量Cr.Cz;在一定范围内,随着粘结相Co、Cr含量的增加,超音速火焰喷涂WC复合涂层显微硬度降低,耐磨粒磨损性能下降,三种涂层中粘结相含量为12%的WC涂层的耐磨粒磨损性能最佳,粘结相含量为17%的WC涂层的耐磨粒磨损性能最差;超音速火焰喷涂Co和CoCr粘结相质量分数分别为12%、14.5%和17%的WC复合涂层在白刚玉磨粒环境中磨粒磨损机制均为微切削和大颗粒WC硬质相疲劳剥落。 展开更多
关键词 超音速火焰喷涂 钻铬粘结相 质量分数 WC复合涂层 磨粒磨损性能
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超高效液相色谱-串联质谱法测定猪肾中安普霉素的残留量
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作者 韩超 周秀锦 +3 位作者 陈瑶 林宇 叶明立 李舟 《分析测试学报》 CAS CSCD 北大核心 2024年第5期787-791,共5页
建立了猪肾中安普霉素残留量的超高效液相色谱-串联质谱(UPLC-MS/MS)测定方法。猪肾样品以磷酸二氢钾溶液提取,经HLB固相萃取柱净化后,采用CAPCELL PAK MGⅡC_(18)(2.0 mm×150 mm,5μm)色谱柱分离,以0.1%甲酸水溶液和甲醇为流动相... 建立了猪肾中安普霉素残留量的超高效液相色谱-串联质谱(UPLC-MS/MS)测定方法。猪肾样品以磷酸二氢钾溶液提取,经HLB固相萃取柱净化后,采用CAPCELL PAK MGⅡC_(18)(2.0 mm×150 mm,5μm)色谱柱分离,以0.1%甲酸水溶液和甲醇为流动相进行梯度洗脱。采用电喷雾离子源正离子模式扫描,多反应监测(MRM)模式进行检测,基质匹配同位素内标法定量。安普霉素在20~200μg/L质量浓度范围内线性良好,相关系数(r^(2))为0.9993,方法定量下限为10.0μg/kg。在10、20、100μg/kg加标水平下的平均回收率为85.5%~94.6%,相对标准偏差(RSD)不大于5.9%。该方法基于HLB固相萃取柱净化,基质匹配同位素内标法定量,具有操作简单、定性准确、灵敏度高的特点,适用于猪肾中安普霉素残留量的测定。 展开更多
关键词 超高效液相色谱-串联质谱法 安普霉素 猪肾 基质匹配 同位素内标
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