基于ICP-MS技术同时测定大米中几种元素的检测方法研究

本实验通过建立微波消解-电感耦合等离子体质谱法(Inductively Coupled Plasma Mass Spectrometry,ICP-MS)测定大米中几种元素的含量,探索一种在相同条件下同时测定大米中几种不同元素的实验方法.实验结果表明,标准曲线相关系数R为0.9998～1.0000,检出限为0.01345...     

应用ICP-MS法测定闽派红曲黄酒中13种元素

目的：应用电感耦合等离子体质谱法（Inductively Coupled Plasma Mass Spectrometry,ICP-MS）同时测定闽派红曲黄酒中Na、Mg、Al、K、Ca、Fe、Cu、Zn、As、Sr、Cd、Hg和Pb等13种元素含量。方法：将闽派红曲黄酒样微波消解后,采用ICP-MS法对13种元素进行同时测定。结果：经试验,该方法在一定的范围内线性良好,各元素平均回收率在88.4%～100.6%,RSD均小于5%。结论：该方法操作简单、样品预处理快速、灵敏度高,适用于闽派红曲黄酒矿物质元素含量测定分析。     

气相色谱法测定蔬菜中4种有机磷农药残留

目的:建立毛细管柱气相色谱法测定蔬菜中64种有机磷农药含量的快速检测方法.方法:以4种有机磷农药为检测对象,通过提取蔬菜中农药残留,GC-FPD测定蔬菜中4种有机磷农药的含量.结果:在0.050～0.500μg·mL-1浓度范围内,农药残留浓度与峰面积具有良好的相关性,加标回收率为81.0％～115.8％,精密度(RS...     

介绍几种仔猪饲料添加剂

要保持仔猪有较高的生长速度和成活率,必须满足其营养需要,除使用常规饲料,添加维生素、矿物质和微量元素外,要根据仔猪的生理特点,合理使用一些添加剂。维生素 E 和生物素在每吨仔猪饲料中添加40～60     

氢化物原子荧光光度法测定稻谷中的无机砷

采用氢化物原子荧光光度法测定稻谷中的无机砷,操作简单、共存元素干扰少、灵敏度高、重复性好,可用于稻谷等粮食中无机砷的测定。     

氢化物原子荧光光度法测定稻谷中的无机砷

阐述了氢化物原子荧光光度法测定稻谷中无机砷的含量,确定了用AFS-2202E型双道原子荧光光度计测定稻谷中无机砷含量的最佳条件。对回收率和精密度进行了测试,提出了测定中的注意事项。标准曲线的线性范围0~14.0 ng/mL,样品加标回收率95.49%－101.40%,空白加标回收率97.53%~107.14%,试样测定...     

3种测定饲料中无机砷的方法比较

将饲料样品通过超声波提取后,利用孔雀绿分光光度法、原子荧光光度法、石墨炉原子吸收法3种方法测定无机砷,探讨3种方法的影响因素,比较了测定结果的准确度和精密度。     

高效液相色谱法测定绿豆糕中的脱氢乙酸

本文建立了绿豆糕中脱氢乙酸的高效液相色谱法快速测定方法,并采用测定绿豆糕样品加标回收率的方法对检测方法进行验证;同时探讨了流动相乙酸铵的pH值变化对脱氢乙酸峰形的影响.结果显示脱氢乙酸浓度与响应值之间的线性关系良好(R2=0.9999),样品的加标回收率为95％～100％,相对标准偏差为1.2％～1.7％;在流动相甲醇...     

东北地区几种蕨类植物的园林利用价值

蕨类是一个古老而重要的植物类群，越来越受到人们的的重视和关注；研究了东北地区7种具园林开发价值蕨类的繁育和栽培。     

东北马鹿和东北梅花鹿再生茸中的氨基酸和无机元素

测定了东北马鹿和东北梅花鹿两种再生茸的化学成分、氨基酸的种类及其含量;再生茸中含有无机元素15种,与头茬茸没有明显差别。     

Price and quantity adjustment in a dual character market The case of the Greek poultry sector

In this paper we set up, estimate and test a short-run model for the poultry sector in Greece. The model allows for the simultaneous existence of a monopolistically competitive and a competitive segment, and determines producer and consumer prices, and the quantity consumed. We provide evidence on steady-state parameters such as demand and supply elasticities, as well as on speeds of adjustment of prices and quantities. The evidence suggests that adjustment is very rapid, although quantities appear to be adjusting more quickly than prices. The model is used to examine the dynamics of adjustment to demand and supply-side disturbances.     

三种木醋液基本参数和组分分析

测定了桦木醋液、柞木醋液和杂木醋液的pH值、有机酸含量和精制得率，结果表明桦木醋液pH值（3．97）最低，杂木醋液pH值（4．21）最高；柞木醋液有机酸含量（5．20％）最高，桦木醋液有机酸含量（2．02％）最低；桦木醋液精制得率（92．2％）相对较高；木醋液稀释倍数与pH值的关系表现为三种木醋液的pH值随着稀释倍数的增加而增加。紫外吸收光谱表明桦木木醋液、柞木醋液和杂木醋液的300倍稀释液在近紫外区的最大吸光度分别为0．400，0．352和0．541；柞木醋液氨基酸总量最高（63．6mg／g），桦木醋液氨基酸总量最低（57．0mg／g）。     

早春花卉侧金盏的抗寒性研究

研究不同低温胁迫下侧金盏叶组织内过氧化物酶（POD）活性、超氧化物歧化酶（SOD）活性、CAT活性、电导率、叶绿素含量及丙二醛含量的变化规律,确定影响其抗寒性的主效因子,探讨低温胁迫下侧金盏的抗寒机理。     

The quantity and variety of households’ meat purchases: A censored demand system approach

This study investigates the demand for 10 disaggregated meat products by U.S. households. A censored demand system which imposes budget constraints in both observed and latent shares is estimated along with a detailed explanation of the estimation procedure. Additional details about the methodology not provided in previous studies should help researchers to empirically apply the model. An innovation of the study is to introduce the censored demand system model for studying the variety of a household's food purchases. Most households buy between seven and eight different products and hardly change the variety of their purchases with changes in meat expenditure.     

葫芦岛市耕地数量变化及其驱动力研究

以1998-2007年的统计资料为基础,分析了葫芦岛市近10年的耕地数量变化特点;通过主成分分析法,对引起耕地数量变化的驱动力进行了研究。结果表明,经济发展、人口增长以及农业科技进步是影响葫芦岛市耕地数量变化的三大驱动力;据此提出了葫芦岛市的耕地保护对策。     

An econometric analysis of demand for food quantity and quality in urban China

This article offers an analytical framework for studying consumer demand for food quality based on a theory‐consistent demand model, namely, the Exact Affine Stone Index specification. Importantly, it accounts for unobserved consumer and regional heterogeneity, and allows for arbitrary Engel curves. The empirical value of our framework is illustrated in an econometric analysis of demand for food quality in China. Evaluating possible structural changes in consumer food expenditures in China is of paramount importance, given the ever‐increasing global role of China and the implications of the structural food preference changes for the global food system. The major findings emerging from this study indicate that income is an important determinant of demand for food quality and quantity with the relatively more affluent provinces having a higher affinity for food quality.     

The role of access to finance in disaster recovery: Evidence from coastal communities in India

Natural disasters affect economic activities and welfare of small-scale producers in developing countries, but may also offer opportunities to reinvest in productive asset, economic capital, and new technologies for future economic prospects. This paper investigates the impacts of a livelihood recovery project that provided access to finance and rehabilitated communal infrastructures in the coastal communities of Tamil Nadu, India which were severely affected by the 2004 tsunami. We replicate the project's eligibility criteria to build the counterfactual to identify control households based on the validation of secondary data and administrative records. Using data from a carefully designed primary survey, we estimate the impacts of providing access to finance and rehabilitating communal infrastructures on economic and livelihood outcomes. Results indicate positive and significant impacts on income, asset and food security. These impacts are mainly driven by improved access to finance provided and participation in groups. Findings highlight the importance of ensuring access to finance for sustainable economic recovery among small-scale producers, particularly in the aftermath of natural disasters.