气相色谱单柱法测定竹节参中20种有机氯农药残留量

为测定竹节参中20种有机氯农药残留,采用超声提取、Florisil硅土柱净化后,采用气相色谱-电子捕获检测器对目标物进行分析测定,内标法定量.结果表明:样品基质3水平添加条件下,20种有机氯农药回收率为68.21%~124.5%,相对标准偏差小于5.64%,检出限为0.009 9~0.049 3μg/kg.该方法快速,准确,灵敏度高,可用于20种有机氯农药残留量测定.     

蔬菜中12种有机氯农药残留的QuEChERS/GC-QqQ-MS/MS测定

建立QuEChERS前处理结合气相色谱-三重四级杆串联质谱(GC-QqQ-MS/MS)法用于测定蔬菜中六六六、狄氏剂、艾氏剂、七氯、五氯硝基苯、氯丹、硫丹等12种有机氯农药残留同时检测的分析方法.样品经乙腈提取,QuEChERS方法净化后,经GC-QqQ-MS/MS在多反应离子监测(MRM)模式下分析测定,外标法定量. 12种有机氯农药在5~100 ng/m L范围内线性关系良好,线性相关系数(R2)超过0. 999 1;在黄瓜样品基质中添加10、40和100 ng/m L 3个浓度水平下,平均加标回收率为68. 80%~97. 18%; RSD(n=6)为0. 95%~11. 07%. 12种有机氯农药的检出限均小于1. 5μg/kg.该法灵敏度高,适用于蔬菜中有机氯农残的检测工作.     

气相色谱测定江永香姜中有机磷农药残留

为建立气相色谱法(GC)测定江永香姜中有机磷农药残留量的分析方法,从永州市江永县采集香姜试样,将试样用含体积比为1%乙酸的乙腈溶液提取,再经无水硫酸镁和醋酸钠净化,以C18色谱柱分离待测物,基质匹配标准溶液外标法定量,最后用气相色谱法(GC)法检测香姜中有机氯农药残留,从而达到定性的效果.试验表明,6种有机磷农药在0~1 mg/L的范围内线性关系良好,相关系数均大于0.990,检出限为0.012~0.071mg/kg,相对标准偏差2.22%~9.30%,试样添加回收试验的平均回收率为68.0%~111.0%.以上结果表明,气相色谱法具有测定有机磷农药种类多、净化效果好、准确度和精密度高等优点,能够满足香姜农药残留检测要求.     

气相色谱法快速测定土壤中9种有机氯农药残留量

目的:建立气相色谱法测定土壤中9种有机氯农药残留量的方法。方法:样品经有机溶剂超声提取,硫酸净化;OV-1701毛细管柱对9种有机氯农药进行分离,电子捕获检测器检测。结果:样品的平均回收率为84.7%~117.1%,RSD为3.36%~7.65%;所测定样品有机氯农药残留量均低于土壤环境质量标准(GB/T 14550-93)。结论:本方法快速、简便、准确,可用于土壤中9种有机氯农药的测定。     

黄芪及其种植土壤中毒杀芬残留量的测定方法

建立了中国传统经典中药材黄芪及其种植土壤中毒杀芬残留量的气相色谱-电子捕获检测器检测方法。粉碎后的黄芪和土壤样品采用正己烷提取毒杀芬后,提取液经PSA(N-丙基乙二胺)和石墨化炭黑固相萃取填料净化,气相色谱-电子捕获检测器测定其毒杀芬含量,外标法定量。方法定量限(信噪比为10∶1)为0.01mg/kg,在0.1~2.0μg/mL的质量浓度范围内,相关系数为0.996,在黄芪和土壤2种样品基质中,0.01,0.02,0.10mg/kg 3个添加水平下,分别平行测定6次,回收率为81%~98%,相对标准偏差(RSD)为2.3%~5.3%,均符合农药残留检测要求。该方法提取效果好,检测灵敏度高,适用于黄芪及其种植土壤中毒杀芬的快速检测。     

气相色谱法测定农产品中8种有机氯农药的残留

建立了气相色谱测定食品中六六六4种同分异构体和滴滴涕4种同分异构体残留量的方法.样品由丙酮/石油醚提取,微型化磺化反应进行净化,采用气相色谱仪测定,外标法定量.结果表明:在5~100 g/L范围内8种有机氯农药的线性良好;所有农药的LOD范围为0.59~5.37 g/kg,LOQ为1.97~17.86 g/kg;在5、10、20 g/kg 3个添加水平下,8种农药的平均回收率在74.0%~106.1%之间,且RSD均小于11%.该方法简单、快速,准确度和精密度高,抗干扰能力强,可用于茶叶、姜、柑橘等农产品中8种有机氯农药的检测.     

六种中药材中的有机氯农药残留量的测定

用气相色谱法同时测定了中药材天仙子、半夏、杜仲、吴茱萸、何首乌、茯苓中的有机氯农药的残留量.结果表明,13种有机氯农药在1~100μg/L范围内线性关系良好(r>0.995 5),检出限为0.04~0.22μg/L,添加回收率均在80%~102%.该方法符合农药残留检测标准.     

液相色谱串联质谱法分析生活饮用水中草甘膦

本方法利用9-芴基甲基三氯甲烷[9-Fluorenylmethylchloro-formate(FMOC-Cl)]衍生化反应后,用液相色谱串联质谱法分析。在0.05mg/L和0.10mg/L两个添加水平下,该方法的回收率为88.0%~102%,精密度RSD为3.52%~5.85%,检出限最低达到0.002mg/L,远低于国家生活饮用水限量标准,适用于饮用水中草甘膦的检测。     

水果和蔬菜中苯醚甲环唑残留量的气相色谱-串联质谱测定方法研究

目的建立气相色谱-串联质谱法测定水果和蔬菜中苯醚甲环唑残留的分析方法.方法试样用乙腈提取,经Sep-Pak Carbon NH2固相萃取柱净化,气相色谱分离,串联质谱多反应监测模式下测定,外标法定量.结果苯醚甲环唑质量浓度在0.01mg/L~2.5mg/L范围内线性关系良好,相关系数R0.996.苯醚甲环唑在不同基质中平均回收率为73.40%~115.1%,相对标准偏差为4.86%~13.24%,检出限为0.005mg/kg.结论该方法灵敏度高,选择性好,抗干扰能力强,适合苯醚甲环唑残留量的定性确证分析和定量分析.     

固相微萃取-气相色谱-串联质谱法测定蜂蜜中双甲脒及其代谢产物残留

建立了同时测定蜂蜜中的双甲脒及其代谢产物2,4-二甲基苯胺残留量的固相微萃取-气相色谱-串联质谱法。对固相微萃取的实验条件(萃取纤维、萃取时间、p H值等)进行了选择和优化,并建立了气相色谱-串联质谱(GC-MS/MS)的仪器检测方法。结果表明:在优化的实验条件下,双甲脒和2,4-二甲基苯胺的最低检出限分别为0.5μg/kg和3.0μg/kg;在0.01~1.0 mg/kg的浓度范围内,二者的添加回收率范围分别为81.9%~98.2%和75.5%~90.6%,相对标准偏差分别为5.0%~15.4%和7.9%~17.2%。该方法操作简便、灵敏度高、准确可靠,适用于蜂蜜中双甲脒及2,4-二甲基苯胺的检测。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-