采用配备GPC纯化装置的GC/MS进行农产品中农药残留的快速分析

本文采用GPC-GC／MS在线连接系统和固相萃取的方法快速测定农产品中的农药残留。该方法首先用液-液分配法从均化的食物样品中提取农药,然后用PSA结合相进行固相萃取,最后进行GPC-GC／MS分析。GPC-GC／MS系统包括一套GPC净化装置,可以简化样品前处理步骤。把浓度为0．1 μg／g的97种农药添加到马铃薯、甘蓝和胡萝卜中,得到了比较好的回收率。整个分析过程大约需要50 min。     

Synthesis of 5,7-Dimethyl-2-(5-Substituted-1,3,4-Oxadiazole-2-yl)- Methylenethio-1,2,4-Triazolo[1,5-a]Pyrimidines as Potential Fungicides

New challenging problems in plant protection technology have promoted research to discover more efficient pesticides. In recent years, many chemists have paid much attention to compounds bearing 1,2,4-triazolo [1,5-a] pyrimidine rings due to their broad spectrum of biological activities such as herbicidal and fungicidal effects1-7. Up to now, a great variety of these kinds of compounds have been synthesized, among which some commercially herbicides have been developed including metosulam, f…     

炭化过程对铁基费托合成催化剂强度和结构的影响

以模型费托合成Fe基催化剂为研究对象,在纯CO气氛中对催化剂进行不同时间的预处理,采用多种手段对预处理后催化剂的物理化学性质和抗磨损能力进行了表征。结果表明,在预处理初期,随着预处理时间的延长,催化剂的炭化程度显著提高,伴随着催化剂比表面积的降低和颗粒粒径的减小,而催化剂的抗磨损能力逐渐提高。当预处理时间超过72 h后,继续延长预处理时间,催化剂的炭化程度不再增加,而积炭程度逐渐增加,伴随着催化剂比表面积和颗粒粒径的增加,催化剂的质量也同时增加,并导致催化剂的抗磨损能力逐渐降低。     

基于挥发性组分的气相色谱指纹图谱评价沉香化气片质量

建立了沉香化气片的气相色谱指纹图谱,并结合化学模式识别评价20批沉香化气片的质量。乙醇超声提取20批沉香化气片的挥发性成分,以正十八烷为内标,分析了3个主要组分的含量,且以内标计算其他各组分的相对峰面积,建立了沉香化气片的气相色谱指纹图谱,确定了11个共有峰,得到了各批次样品的相似度,并通过气相色谱-质谱法和对照品比对对10个共有峰进行了指认。将获得的峰面积指纹图谱采用系统聚类分析和主成分分析进行化学模式识别研究,实现了不同批次沉香化气片的区分,发现了造成不同批次样品差异的主要标记物。该方法有效且综合性强,为科学评价与有效控制沉香化气片的质量提供了可靠的参考。     

A UNIFIED ISOSTATIC DATUM AND ITS APPLICATION IN SEA LEVEL CHANGE RESEARCH

The necessity of establishing a Unified Isostatic Datum (UID) for studying the sea levelchanges along the coast of China is discussed in this paper. A so-called Coastal Land Ver-tical Movement Isostatic Datum (CLVMID) is established based on precise releveling dataperformed from the 1950s to 1980s and some coniunction releveling data with tide stations.All the data consists of about 250,000 km releveling lines and covers the whole mainland ofChina. As examples, datum corrections for sea level changes derived from two tide stationsand recent crustal vertical movement in the Yangtse Delta area relative to the datum aregiven to explain the significance of the isostatic datum in the research of the sea levelchange trend.     

PAR螯合树脂相光度法测定钯

树脂相光度法是一种灵敏、快速、简单的分离富集与测定同时进行的新型方法[1 ,2 ] 。该方法以离子交换树脂作载体 ,直接对显色树脂进行光度测定 ,避免了洗脱、分离等复杂过程 ,使灵敏度得到了很大提高 ,迄今为众多研究者关注[3] 。铂族金属钯的光度分析法报道较多[4] ,但迄今少见用树脂相光度法测定钯的报道。星野仁等[5 ,6] 指出在ＥＤＴＡ ＮａＯＨ 硼砂介质中 ,ＰＡＲ Ｐｄ(Ⅱ )配合物与十四烷基二甲基苄基氯化铵形成离子缔合物 ,该缔合物能被ＣＨＣｌ3定量萃取 ,其摩尔吸光系数为 3.2 9× 1 0 4 ,方国桢等[7] 确定了在ＥＤ ＴＡ ＮａＯ…     

GAMMA FAMILY EVENTS WITH LARGE-SEPARATION DOUBLE CORES

A peculian cosmic ray double core event K5618 was recently found in Mt.Kanbala emulsion chamber,with the following characteristic quantities:zenith angle=27°,total visible energy ΣE_γ=547TeV;energies of the two cores E₁=428TeV and E₂=119TeV with the separation between them R₁₂=25.56cm.it is expected that such an event might give some indication of the signal of the production of extraordinarity large transverse momentum particles in super high energy hadronic interactions.     

竹红菌乙素对人红细胞膜蛋白荧光猝灭机理的研究

本文利用人红细胞膜蛋白内源荧光(主要指色氨酸),经加入不同的竹红菌乙素之后,引起了荧光猝灭现象,根据荧光猝灭原理分别从吸收光谱,荧光光谱,稳态变温实验和瞬态荧光等技术分析了上述的猝灭过程,实验证明:该猝灭是以动态碰撞过程为主要作用机理,据此作者提出了乙素可以用于生物膜体系的蛋白质荧光猝灭剂的理由。     

Nuclear Fermi Motion Effect on Pion Double Charge Exchange

The influence of nuclear Fermi motion on the conventional mechanism of pion double charge exchange (DCX) is examined.Concrete calculations of the 0° excitation function over the energy region 0—300MeV are performed for the double isobaric analog DCX transition on ¹⁴C.The calculated results coincide very well with the experimental data for the energies above 100MeV,but are about a factor of 2—3 smaller than the experimental data around 50MeV.It indicates that the pure conventional mechanism seems incapable to fully explain the anomalous behavior of the low energy DCX,and some new mechanisms are needed.     

多功能复合材料结构状态感知系统

由于具有比强度和比刚度高、可设计性强等优点,先进复合材料正在逐步成为新一代民用飞机的主要结构材料。为了充分利用复合材料的优越性能,有必要研发一种与复合材料结构集成一体的多功能传感系统,以使复合材料结构可以"感觉"和"思考"自身状态。本文提出一种类似于人体神经系统的多功能传感器网络系统,将不同功能的传感器有机结合起来,并与复合材料结构永久集成于一体,用来感知结构应变、温度、湿度、气动压力等参量,并监测发生在结构上的外界撞击及内部损伤。利用这一新概念设计和制造的未来复合材料结构可以提供多种模式的综合信息,从而使之具有智能传感、环境适应等多种功能。本文同时也讨论了发展这样一种多功能结构状态感知系统所面临的挑战与有关解决途径。