用转移矩阵法数值研究二维正方介质柱光子晶体的传输特性

利用转移矩阵方法对二维正方介质柱光子晶体的传输特性进行了研究,数值计算研究了不同晶格、同一晶格柱体截面面积不同、放置方位角不同时光子晶体的传输特性。数值结果表明光子禁带的宽度与中心频率和晶格结构有很大关系,正方晶格更易形成平坦光子禁带,柱体截面面积大,则形成的禁带较宽,在其他因素相同的条件下柱体放置的方位角对光子禁带有重要影响。数值研究表明在正方介质柱下设计宽平坦光子禁带时,可以首先考虑正方晶格结构,其次设法使柱体截面尽量大一些,最后可通过柱体放置方位角来微调光子禁带的宽度与中心频率以达到设计要求。     

Analytical methodologies for aluminium speciation in environmental and biological samples – a review

It is recognized that aluminium (Al) is a potential environmental hazard. Acidic deposition has been linked to increased Al concentrations in natural waters. Elevated levels of Al might have serious consequences for biological communities. Of particular interest is the speciation of Al in aquatic environments, because Al toxicity depends on its forms and concentrations. In this paper, advances in analytical methodologies for Al speciation in environmental and biological samples during the past five years are reviewed. Concerns about the specific problems of Al speciation and highlights of some important methods are elucidated in sections devoted to hybrid techniques (HPLC or FPLC coupled with ET–AAS, ICP– AES, or ICP–MS), flow-injection analysis (FIA), nuclear magnetic resonance (²⁷Al NMR), electrochemical analysis, and computer simulation. More than 130 references are cited.     

钛－硅沸石的结构表征及其催化性能

ＸＲＤ，ＩＲ，２９ＳｉＭＡＳＮＭＲ，ＵＶ－ＶＩＳ及ＸＰＳ能谱表征证实钛原子进入了钛－硅五元环沸石的骨架晶格位（不含铝）．ＴＧ－ＤＴＡ结果表明，钛原子进入沸石骨架导致沸石骨架的热稳定性提高，超过１４７３Ｋ．氯丙烯与Ｈ２Ｏ２（３０％）的环氧化反应结果表明钛－硅沸石具有优异的氧化性能，这也从另一个侧面证实了钛原子位于沸石骨架晶格位．     

二苯并噻吩分子印迹功能化MOF199吸附剂的制备及性能

结合分子印迹技术,MOF199为基体,以二苯并噻吩(DBT)为模板分子,甲基丙烯酸(MAA)为功能单体,制备了新型表面分子印迹聚合物材料MOF@SMIP。采用SEM、BET、FT-IR等对其结构和形貌进行表征,在模拟油样中进行吸附评测,吸附平衡时间为1.5 h。MOF@SMIP对DBT吸附量为130.73 mg/g较MOF199吸附量37.79 mg/g有很大提升,同时MOF@SMIP吸附量对比MOF@NIP吸附量(57.13 mg/g)优势明显,印记因子f_(imp)为2.29。吸附行为遵循伪一阶动力学模型说明吸附主要为物理过程。选择性吸附实验表明,MOF@SMIP对目标分子DBT表现出比对结构类似物苯并噻吩(BT)和联苯更高的亲和力,吸附DBT对干扰物BT和联苯的相对选择系数k'分别达到2.55和2.14。