脉冲差分方程的两度量稳定性

利用李雅普诺夫函数和新的比较原理讨论了脉冲差分方程的两度量稳定性问题.     

合成气一步法制备二甲醚核壳结构催化剂的制备及其反应性能

以生物质(葡萄糖、蔗糖、淀粉)为模板剂,通过水热合成法制备具有核壳结构的CuO-ZnO-Al₂O₃@Al₂O₃复合催化剂,该催化剂以甲醇合成催化剂CuO-ZnO-Al₂O₃为核,甲醇脱水催化剂Al₂O₃为壳.SEM-EDS对催化剂核壳结构的表征发现,通过改变水热合成温度和合成时间可以调变催化剂中Al₂O₃壳层的厚度.将该复合催化剂用于合成气直接制备二甲醚的反应,在空速1 500 mL/(h·g_cat)、温度260 ℃、压力5.0 MPa的条件下,CO转化率和二甲醚选择性分别达到35.2%和61.1%.     

S-烷基O-芳基硫代磷酸衍生物的合成及其杀虫活性的研究

研究了O,O-二烷基O-芳基硫代磷酸酯与三氧氧磷的异构化氯化反应。由此生成的S-烷基O-芳基硫代磷酰再与亲核试剂(醇,酚,硫醇,硫酚,伯胺或氨)在缚酸剂存在下反应,合成了42种化合物,其中34种未见文献报道。本文还研究了这类化合物的杀虫活性。     

大口径毛细管柱气相色谱法分析三氯杀螨醇

A method of quantitative analysis for dicofol by a wide bore capillary column has been studied. The gaschromatographic conditions were as follows.Column:fused silica, HP-1(cross-linked methyl silicone)5m ×0.53mm × 2.65μm film;column temperature : 200℃;temperature of injector and detector: 250℃ and carriergas:H_2 25mL/min. Dioctyl phthalate was used as the internal standard.10% of dicofol would be decomposedquantitatively to dichlorobenzophenone.     

pH敏感型聚谷氨酸/透明质酸基互穿网络医用水凝胶的制备及表征

生物材料是推动生物医学领域日新月异变化的基石,医用水凝胶作为重要成员,近年来表现出蓬勃发展的态势。文章介绍了一种新型可注射的、以生物相容性方法交联的聚谷氨酸(Poly (γ-glutamic acid), PGA)/透明质酸(Hyaluronic acid, HA)复合水凝胶。研究首先采用EDC/NHS方法合成了酪胺(Tyramine,Ty)接枝聚谷氨酸的PGA-Ty前体大分子及半胱胺(Cysteamine, CA)修饰透明质酸的HA-CA前体大分子。两种前体大分子的结构分别使用核磁和红外进行了确证。得到的两种前体大分子在低浓度双氧水和辣根过氧化物酶(Horseradish Peroxidase, HRP)的共同作用下,于水相中交联得到互穿网络(Interpenetrating Network, IPN)水凝胶。实验对IPN水凝胶样品的系列性能,如平衡含水量、内部形貌、酶降解速率以及力学性能等进行了测试,并选取了盐酸四环素为药物模型对凝胶的体外药物释放行为、体外抗菌效果进行了测评。凝胶材料的细胞毒性及凝胶支架对细胞3D培养的效果证明其生物相容性优异,体外包埋的细胞经72h培养,未表现出明显细胞毒性。系列数据证明,该种水凝胶可以设计成为pH敏感型的药物控释载体材料,并因其良好的生物相容性,也有作为细胞支架、创伤辅料等其它生物医用材料的潜力。     

A novel method to measure the isotope shifts and hyperfine splittings of all ytterbium isotopes for a 399-nm transition

We report the experimental results on measuring the isotope shifts and hyperfine splittings of all ytterbium isotopes for a 399-nm transition by using a quite simple and novel method.It benefits from the advantages of the modulation transfer spectroscopy in an ytterbium hollow cathode lamp and the Doppler-free spectroscopy in a collimated ytterbium atomic beam.The key technique in this experiment is simultaneously measuring the frequency separations of the two spectra twice,and the separation difference between two measurements is solely determined by the well-defined frequency of an acousto-optics modulator.Compared with the most of previously reported experimental results,ours are more accurate and completed,which will provide the useful information for developing a more accurate theoretical model to describe the interaction inside an ytterbium atom.     

Frequency stabilization of a 399-nm laser by modulation transfer spectroscopy in an ytterbium hollow cathode lamp

The modulation transfer spectroscopy in an ytterbium hollow cathode lamp at 399 nm is measured. The error signal for frequency locking is optimized by measuring the dependences of its slope, linewidth and magnitude on various parameters. Under the optimum condition, the laser frequency at 399 nm can be stabilized. The long-term stability of laser frequency is measured by monitoring the fluorescence signal of the ytterbium atomic beam induced by the locked laser. The laser frequency is shown to be tightly locked, and the stabilized laser is successfully applied to the cooling of ytterbium atoms.     

用大口径毛细管柱定量分析灭多威

国外推荐灭多威的定量分析方法是高压液相色谱法,残留分析用气相色谱法,但需要将灭多威转化成甲基-N-羟基硫代乙酰亚胺酸酯,再进行定量分析。高压液相色谱仪,因其价格昂贵,普及程度远不如气相色谱仪。灭多威是当前国内大力开发的氨基甲酸酯杀虫剂,因此研究其分析方法,具有明显的实际意义。用大口径毛细管柱代替填充柱对农药进