载镍沸石上NH3-TPD脱附峰的非酸性探讨

NH_3-TPD技术表征固体催化剂的酸性似乎已很成熟,其实不然。如该技术表征HZSM-5沸石时,有作者观察到773K左右的高温脱氨峰,而有些作者则检测不到。诚然,各作者间所用试样及预处理条件等存在差异,但实验装置和实验操作条件不同带来的影响也不可忽视。此外,该技术在用于表征一些新的较复杂的催化剂时,其程脱谱也会呈现出新现象,这些现象有时是不能通过酸性来解释的,这是因为NH_3作为探针分子不仅具有碱性,同时还有还原性和配位性。本文对载镍沸石上NH_3-TPD谱图中出现的某些新峰进行了剖析和归属。     

Cesium lead halide perovskite nanocrystals for ultraviolet and blue light blocking

Using cesium lead halide perovskite nanocrystals, CsPb(Cl/Br)_3, as a light absorber, we report a highly effective UV and blue light blocking film. The CsPb(Cl/Br)_3 nanocrystals are well dispersed in the ethyl cellulose(EC) matrix to compose a UV and blue light shielding film, and the absorption edge of the film is tunable by adjusting Cl to Br ratio using anion exchange. The CsPbCl_2 Br-EC film exhibits a transmittance of 5% at 459 nm, 90% at 478 nm and 95% in the range of 500–800 nm, which makes it excellent for UV and blue light shielding. In addition, the as-prepared EC-CsPb(Cl/Br)_3 film shows excellent photostability under UV irradiation. Results demonstrate that this EC-CsPb(Cl/Br)_3 based materials with sharp absorbance edges, tunable blocking wavelength, and high photostability can be useful for the applications in UV and blue light blocking and optical filters     

用裂解气相色谱法对几株霉菌的分析

本文用带有PYR-2A管式炉裂解器和C-R2AX计算机的岛津GC-9A气相色谱仪,对3株曲霉和3株青霉进行了裂解气相色谱鉴别。通过对指纹图的分析,能够较好地区分出两属之间和各菌株之间的差异,证明了裂解气相色谱分析法用于霉菌鉴别的可能性。     

Unlabeled Fluoroimmunoassay with a Europium Chelate

Unlabeled fluoroimmunoassay with a europium chelate is described. The recommended method is simple because the complicated labeling process is omitted. The recovery of some samples ranges from 91 to 111%. The relative standard deviation of the method is less than 10%. The detection limit is about 10⁻¹⁰mol liter⁻¹antigen.     

氢化物发生石墨炉原位富集直接测定高温镍基合金中碲

通过选择碲的氢化物发生条件，克服了高含量镍对碲的干扰，把氢化物富集在涂钯石墨管里，然后再原子化，成功地测定了高温镍基合金中碲。     

用原子捕获技术提高火焰原子吸收光谱法的灵敏度

采用简易的石英原子捕获器，使Ｃｕ，Ａｇ，Ａｕ，Ｚｎ，Ｃｄ，Ｐｂ，Ｓｂ，Ｂｉ等易挥发元素在空气－乙炔火焰原子吸收光谱法中的灵敏度提高了３～５倍，并有较好的精密度，相对标准偏差在１％左右，方法中用此技术测定了标准物质中Ｐｂ、Ｃｄ的含量，获得了满意的结果，它较之石墨炉原子吸收光地具有快速，简便的特点，具有较大的实用价值。     

Li2O·nB2O3-20%LiCl-H2O体系20℃过饱和溶液结晶动力学研究

用动力学方法对Li₂O·nB₂O₃-20%LiCl-H₂O体系(n=1,2,3)20℃过饱和溶液结晶过程进行研究，结果表明每一种溶液只析出一种固相，Li₂O∶B₂O₃=1∶1、1∶2和1∶3的氯化锂溶液分别结晶出Li₂O·B₂O₃·4H₂O, Li₂O·2B₂O₃·3H₂O和Li₂O·5B₂O₃·10H₂O，拟合并给出结晶动力学方程，同时对这三种固相的结晶反应机理进行了探讨。     

基地建设经验交流

南京大学化学化工学院于1991年被国家教委批准为首批国家基础科学研究和教学人才培养基地."基地方案的制定和实施"于1997年获国家教委优秀教学成果二等奖,并于1998年在国家自然科学基金委组织的中期评估中获得优秀基地的称号,1999年又以优异成绩顺利通过了教育部组织的基地挂牌验收.     

电解沉积压电频移分析的理论与验证

提出了控制电位电解和恒电流电解两类电解沉积的压电频移分析法测定的理论公式,用实验结果验证了它的正确性.     

Construction and analytical application of ion-selective piezoelectric sensor for atropine sulfate

The method describes the use of a piezoelectric quartz crystal (PQC) as a substitute for ion-selective electrodes. The approach is feasible when the membrane materials are electrically non-conductive and membrane potential measurements are consequently not possible. An ion-selective piezoelectric sensor sensitive to atropine sulfate was constructed by coating a PVC membrane containing activant on one the side of a PQC. On the basis of selective adsorption of atropine ions across the modified film and the sensitive mass response of PQC, the method exhibits a sensitive, rapid response and is easy to operate without pretreatment of the sample. The logarithm of the frequency shift gave a linear relationship with the logarithm of atropine sulfate concentration in the 1.0 x 10(-8)-1.0 x 10(-3) M range with a detection limit of 5.0 x 10(-9) M at pH 7.0. Recoveries were from 98.7-102.2%. Two activants, atropine tetraphenylborate and atropine dipicrylaminate, were synthesized and investigated. Influencing factors were also examined and optimized. The results for real samples obtained by the proposed method agreed with those obtained by conventional methods.