HPLC快速测定鸡肉中二氯二甲吡啶酚残留

本实验研究一种快速，简便的测定鸡肉中二氯二甲吡啶酚残留量的高效液相色谱法。本法采用微量化技术处理样品，以乙腈－氯仿为提取剂提取样品中残留的二氯二甲吡啶酚，提取液经挥发干后，在正已烷和硫酸钠水溶液两相间进行分配以去除脂类物质，然后再用乙腈－氯仿人中将二氯二甲吡啶酚提取出来，将有机相挥发至干，残渣定量溶解于流动相中，以ＲＰ－ＨＰＬＣ分离，紫外检测器于２６５ｎｍ波长下检测，外标法定量。空白鸡肉样品添加     

5—Br—PNPFF与镍（Ⅱ）的显色反应及其分析应用

研究了新试剂1-(5’-溴-2’-吡啶基)-5-(4’-硝基苯基)-3-(2’-呋喃基)甲■(5-Br-PNPFF)与镍(Ⅲ)的显色反应条件。在吐温-80存在下,pH5.0的邻苯二甲酸氢钾-氢氧化钠缓冲介质中,镍(Ⅲ)与5-Br-PNPFF形成1:2的深绿色配合物,其最大吸收峰在7 10nm处,ε_(710)=4.89×10~4 L/mol.cm~(-1)。选择性好,镍含量在0～300μg/L范围内符合比尔定律。用所拟方法测定钢铁中的微量镍,结果满意。     

The preparation of terephthalic acid by solvent-free oxidation of p-xylene with air over T（p-C1）PPMnC1 and Co（OAc）2

An attempt has been made to prepare terephthalic acid（TPA） by solvent-free oxidation of p-xylene（PX） with air over tetra（pchlorophenylporphinato） manganese chloride（T（p-Cl）PPMnCl） and cobalt acetate.The co-catalysis between T（p-Cl）PPMnCl and Co（OAc）₂ has been discovered under solvent-free conditions.TPA yield could be increased significantly when T（p-Cl）PPMnCl and Co（OAc）₂ were used together.The addition of T（p-Cl）PPMnCl into the reaction mixture over Co（OAc）₂ significantly accelerated the rate-determining step of the oxidation process of PX to TPA.The effect of temperature on reaction was also investigated.     

Simultaneous Impedance Analysis of Three Parallel Piezoelectric Quartz Crystals for Electrochemical Depletion Layer Effect Study

Simultaneous impedance analysis of three one-face sealed resonating piezoelectric quartz crystals (PQCs) in parallel is proposed through admittance measurements of the three PQCs on one impedance analyzer and then non-linear fitting according to the parallel combination of three Butterworth-Van Dyke circuits. Responses of each PQC obtained from the three-PQC mode agreed well with those measured separately in series sucrose aqueous solutions. This novel method has been used for the study of depletion-layer effect during ferri-/ferrocyanide electrochemical reactions.     

A new flavonoid from Selaginella tamariscina

6-(2-Hydroxy-5-acetylphenyl)-apigenin (1),a new flavonoid with a phenyl substituent,was first isolated from Selaginella tamariscina.Its structure was elucidated on the basis of 1D and 2D NMR as well as ESI-HR-MS spectroscopic analysis.     

应用壳聚糖-分子筛复合材料选择性吸附卷烟烟气中低分子醛酮

制备了3种壳聚糖-分子筛复合材料,并使用扫描电镜和ASAP 2020全自动吸附仪观测了复合材料的微观形态及其物理性质。对分别添加3种壳聚糖-分子筛复合材料、分子筛及壳聚糖的卷烟复合滤咀对主流烟气中低分子醛酮类化合物和其它有害物质(如焦油、尼古丁及一氧化碳等)的吸附效果进行了试验。结果表明:添加了壳聚糖-分子筛复合材料、分子筛及壳聚糖的卷烟滤咀对主流烟气中低分子醛酮类化合物均有较好的吸附作用,对焦油、烟碱量无明显影响;3种壳聚糖-分子筛复合材料对主流烟气中醛酮类化合物的吸附能力均优于其两种单体材料,该复合材料对一氧化碳有一定的吸附,且对抽吸品质有所改善,口感柔和,烟气刺激性降低。     

Real-time monitoring of DNAzyme cleavage process using fluorescent assay

Detection of deoxyribozyme(DNAzyme) cleavage process usually needs complex and time-consuming radial labeling,gel electrophoresis and autoradiography.This paper reported an approach to detect DNAzyme cleavage process in real time using a fluorescence probe.The probe was employed as DNAzyme substrate to convert directly the cleavage information into fluorescence signal in real time.Compared with traditional approach,this non-isotope method not only brought a convenient means to monitor the DNAzyme cleavag...     

作用在有限线性空间上基柱为F_4(q)的几乎单群

线传递线性空间可以分为非点本原和点本原两种情形,而点本原的情况又可以分成基柱为初等交换群或非交换单群两种情形.本文考虑后一种情形,即T是非交换单群,T≤G≤Aut(T)且G线传递,点本原作用在有限线性空间上的情形.证明了当T同构于F_4(q)时,若T_L不是~2F_4(q),B_4(q),D_4(q).S_3,~3D_4(q).3,F_4(q~(1/2))和T的抛物子群的子群时,T也是线传递的,这里q是素数p的方幂.     

Ni-Co-W-B非晶态催化剂的制备及其加氢脱氧性能

采用化学还原法制备了不同Ni/Co原子比的Ni-Co-W-B非晶态催化剂,以苯酚为探针,研究了其加氢脱氧性能.结果表明,新鲜的Ni-Co-W-B催化剂具有非晶态结构,其中Ni0和B0之间存在电子转移,且随着Co含量的增加,催化剂的热稳定性逐渐提高,表面Ni0含量减少.该催化剂上苯酚加氢脱氧反应按照先加氢再脱氧的方式进行...     

拟生灭过程几种遍历性的判别准则(Ⅱ)

本文是文[7]的继续,研究了连续时间拟生灭过程,给出了一类连续时间拟生灭过程l-遍历和几何遍历行之有效的判别准则,并证明其不可能是多项式一致遍历和强遍历的.