气相色谱法鲫鱼脂肪酸的测定

对鲫鱼鱼油的提取方法进行了研究,用气相色谱法测定了其中脂肪酸的组成及含量.结果表明,鲫鱼含油率高达47%,鱼油中含有多种脂肪酸,其中不饱和脂肪酸含量达69.5%.     

QuEChERS提取与高效液相色谱-电喷雾电离串联质谱联用法检测茶叶中的19种农药残留

建立了高效液相色谱-电喷雾电离串联质谱同时检测茶叶中阿维菌素、啶虫脒、涕灭威、甲萘威、克百威、萎锈灵、除虫脲、烯酰吗啉、唑螨酯、吡虫啉、茚虫威、甲霜灵、灭多威、腈菌唑、咪酰胺、丙环唑、鱼藤酮、西玛津、戊唑醇19种农药残留的方法.试样经QuEChERS方法进行前处理,超高效液相色谱-电喷雾电离串联质谱法测定,外标法定量....     

Preparation and Acid Catalytic Activity of TiO2 Grafted Silica MCM-41 with Sulfate Treatment

TiO2 grafted silica MCM-41 catalyst with and without sulfate treatment were prepared. The structural and acid properties of these materials were investigated by XRD, N2 adsorption-desorption, element analysis, thermal analysis, Raman and FTIR measurements. Their acid-catalytic activities were evaluated using the cyclization reaction of pseudoionone. It was found that the obtained materials possess well-ordered mesostructure, and the grafted TiO2 components were in highly dispersed amorphous form. T/MCM41 without sulfation contained only Lewis acid sites, while Br?nsted and Lewis acidities were remarkably improved for the sulfated materials ST/MCM41 and d-ST/MCM41. T/MCM-41 was not active for the cyclization reaction of pseudoionone, but ST/MCM-41 and d-ST/MCM-41 possessed favorable catalytic activities. The catalytic performance of ST/MCM-41 was comparable with that of the commercial solid acid catalyst of Amberlyst-15, and better than that of d-ST/MCM-41, although the latter underwent a second TiO2 grafting process and accordingly had higher Ti and S content. The specific surface structure of Si-O-Ti-O-S=O in ST/MCM-41 and the bilateral induction effect of Si and S=O on Si-O-Ti bonds were speculated to account for its higher acid catalytic activity.     

A Three-Dimensional Velocity-Map Imaging Setup Designed for Crossed Ion-Molecule Scattering Studies

In this study, we report the design and simulation of an electrostatic ion lens system consisting of 22 round metal plates. The opening of the extractor plate is covered with metal mesh, which is for shielding the interaction region of the lens system from the high DC voltages applied to all other plates than the repeller and extractor plates. The Simion simulation shows that both velocity-mapping and time focusing can be achieved simultaneously when appropriate voltages are applied to each of the plates. This makes the ion lens system be able to focus large ionic volumes in all three dimensions, which is an essential requirement for crossed ion-molecule scattering studies. A three-dimensional ion velocity measurement system with multi-hit and potential multi-mass capability is built, which consists of a microchannel plate (MCP), a P47 phosphor screen, a CMOS camera, a fast photomultiplier tube (PMT), and a high-speed digitizer. The two velocity components perpendicular to the flight axis are measured by the CMOS camera, and the time-of-flight, from which the velocity component along the flight axis can be deduced, is measured by the PMT. A Labview program is written to combine the two measurements for building the full three-dimensional ion velocity in real time on a frame-by-frame basis. The multi-hit capability comes from the fact that multiple ions from the camera and PMT in the same frame can be correlated with each other based on their various intensities. We demonstrate this by using the photodissociation of CH₃I at 304 nm.     

天麻多糖对小鼠移植性肿瘤的抑制作用

探讨天麻多糖对小鼠移植性肿瘤的抑制作用和抗癌机制,选择不同计量的天麻多糖连续15天为荷瘤小鼠灌胃给药,停药后24小时处死小鼠,取瘤组织称重及测体积,并将瘤组织做病理观察．结果表明天麻多糖对肿瘤重量的抑制率为33．9—39．7％;对肿瘤体积的抑制率为34．2—50．6％．病理切片可见用药组瘤组织有大量炎性坏死．天麻多糖对瘤细胞可形成炎性浸润,破坏肿瘤细胞增殖和提高荷瘤小鼠机体免疫力等,因而具有抑制肿瘤的作用．     

天麻中多糖的提取、纯化及含量分析

采用水浸提的方法提取了天麻中的多糖,并进行了纯化和含量分析,同时对影响天麻多糖提取的因素进行了考察.实验结果表明,在选择的最佳提取条件下,天麻中粗多糖得率为12.93%,纯化后多糖得率为9.22%,纯化多糖中多糖含量的为54.57%,粗多糖中多糖含量为38.42%.     

社会融合背景下新生代农民工利益抗争过程中的策略选择研究——基于博弈论的视角

本文从农民工群体与企业利益抗争过程中的策略选择入手,通过决策树和序贯博弈理论与数值仿真的方法,探讨了农民工群体依法维权的相对成本与企业失信的相对违法成本在不同的系统参数下对于农民工利益抗争过程中的策略选择的影响,并探究不同系统参数下农民工群体的均衡策略,提出均衡状态下,系统参数之间应满足的条件关系表达式。研究表明:依法维权的成本过高虽然对农民工群体的策略选择有影响,但并不是导致农民工群体更倾向于选择亲群体性行为的根本原因。提高企业失信违法成本并不会有效的避免农民工群体利益受损,减少农民工群体选择亲群体性行为。亲群体性行为其真正的原因在于体制内维权困难。政府应该减少依法维权的成本,同时应尽量减少群众的“闹大”意识,加强群众依法维权的法律意识。     

羽毛球专业课运用比赛教学法的实验研究

以河池学院体育系07和08级的羽毛球选修班学生为研究对象,在08级羽毛球选修班教学中运用比赛教学法进行教学,通过与07级羽毛球选修班对比,探讨比赛教学法在羽毛球专业课中的作用,从而为本专业的教学改革提供参考.研究结果表明,实验班在技术动作的掌握和控球能力上都优于对照班,达到了增强学习兴趣和提高课堂教学质量的目的.     

Cu/ZrO_2催化剂的结构及其CO_2加氢合成甲醇催化反应性能

采用低温氮气吸脱附、XRD、TPR、In-situ IR和XPS等表征手段,对分步沉淀法、浸渍沉淀法和固态反应法制备的CuO/ZrO2催化剂进行表征,同时考察了其CO2加氢合成甲醇反应性能。结果表明,制备方法对CuO/ZrO2的物理结构和还原性能影响很大,其中浸渍沉淀法制备的催化剂Cu与ZrO2相互作用最强,并显示了较高的CO2转化率和甲醇收率。Cu与ZrO相互作用的强弱直接影响CO加氢合成甲醇反应性能的优劣,而催化剂的比表面积不是影响反应性能的主导因素。     

A colorimetric assay for measuring iodide using Au@Ag core–shell nanoparticles coupled with Cu

Au@Ag core–shell nanoparticles (NPs) were synthesized and coupled with copper ion (Cu²⁺) for the colorimetric sensing of iodide ion (I⁻). This assay relies on the fact that the absorption spectra and the color of metallic core–shell NPs are sensitive to their chemical ingredient and dimensional core-to-shell ratio. When I⁻ was added to the Au@Ag core–shell NPs-Cu²⁺ system/solution, Cu²⁺ can oxidize I⁻ into iodine (I₂), which can further oxidize silver shells to form silver iodide (AgI). The generated Au@AgI core–shell NPs led to color changes from yellow to purple, which was utilized for the colorimetric sensing of I⁻. The assay only took 10 min with a lowest detectable concentration of 0.5 μM, and it exhibited excellent selectivity for I⁻ over other common anions tested. Furthermore, Au@Ag core–shell NPs-Cu²⁺ was embedded into agarose gels as inexpensive and portable “test strips”, which were successfully used for the semi-quantitation of I⁻ in dried kelps.