模拟水中铜镍合金B10耐蚀性的光电化学研究

采用循环伏安、光电化学和电化学阻抗谱技术对模拟水中铜镍合金B10的腐蚀行为进行了研究.在电位从正往负向扫描中 B10表面膜显示p-型光响应,光响应来自电极表面的Cu2O层,但最大光电流比硼砂-硼酸中的要低。B10电极的耐蚀性能随着溶液中Cl-、SO42-和S2-浓度及pH的增加而降低。温度的升高会导致光电流由p-型转为n-型,耐蚀性能急剧下降。电化学阻抗谱测量结果与光电化学方法得到的结果相一致。     

微波辅助有机过氧化物功能化修饰单壁碳纳米管

本文报道了微波辅助下,利用过氧化月桂酰分解得到的十一烷基,化学功能化修饰单壁碳纳米管。这种快速、高效的方法将反应时间缩短至10分钟,并得到了比传统回流方法具有更高接枝率的产物。利用傅立叶变换红外光谱(FT-IR),热失重分析(TGA),拉曼光谱,探究了不同的反应时间和微波功率对单壁碳纳米管的接枝率的影响。结果表明：过长的反应时间会导致部分的去功能化的发生,而过高的微波功率(大于900瓦),则会将单壁碳纳米管上起初键连上的十一烷基剥落下来。分散性照片和高分辨率透射电子显微镜(HRTEM)照片显示出,功能化后的单壁碳纳米管与原始的碳管相比,在有机溶剂中的分散性有了明显的提高。     

中草药中有机磷及氨基甲酸酯类农药残留量的GC-MS测定

气相色谱-质谱法同时测定中草药中多种有机磷及氨基甲酸酯类农药残留量.采用V(乙腈)∶V(丙酮)＝3∶7混合溶剂微波辅助提取,弗罗里硅土和中性氧化铝层析柱净化,气相色谱-质谱(GC-MS)联用检测,农药混标在0.01～1.0 μg/mL范围内线性良好,在0.5、0.1、0.05 μg/mL 3个水平添加平均回收率分别为86.5%～110.6%、81.2%～108.3%和72.9%～122.3%,相对标准偏差分别为2.6%～8.3%、4.6%～9.7%和2.3%～10.7%.     

F-T合成校正综合动力学模型

考虑了烯烃、醇与酸的再吸附及其非本征效应(烯烃、醇与酸在催化剂孔道中的扩散作用、物理吸附及溶解度效应)对产物分布的影响,推导了基于详细反应机理的亚甲基插入的烷基机理F-T合成校正综合动力学模型.利用文献数据对动力学模型进行了回归,获得了与文献报道结果相一致的动力学参数.由校正动力学模型计算的烷烃、烯烃、醇与酸产物分布及烯烃比、醇烃比及酸烃比与实验数据较好地吻合.动力学计算结果表明,在铁锰催化剂上,烷烃、烯烃、醇与酸生成的反应是平行竞争反应,烯烃、醇与酸在催化剂表面的再吸附及二次反应导致产物分布偏离了ASF分布.动力学研究还表明,相同碳数的醇与酸产物在催化剂表面上再吸附及二次反应的机会比相同碳数的烯烃大.通过比较相同碳数的烯烃、醇与酸的分子体积及沸点,指出了在铁锰催化剂上,低碳数的烯烃、醇与酸的再吸附及二次反应对产物分布影响的非本征效应中,烯烃、醇与酸的扩散阻力不是主导效应.     

基于手性18-冠-6-四羧酸络合作用的毛细管电泳分离β-氨基酸对映体

以D-(-)-酒石酸和一缩二乙二醇为原料,合成了(-)-18-冠-6-四羧酸(18C6H4),并将18C6H4作为手性添加剂,应用于β-氨基酸对映体的毛细管电泳分离。考察了背景电解质溶液(BGE)中18C6H4的浓度、BGE pH值、BGE组成、有机改性剂及运行电压等因素对分离的影响。在优化的分离条件下,即BGE的组成为10 mmol/L18C6H4,10 mmol/LTris,pH2.20,紫外检测波长为254 nm,所测试的5种β-氨基酸的出峰时间均在25 min内,分离因子1.04~1.08,分离度0.46~1.52。结果表明该方法简便快速,可方便地用于β-氨基酸对映体的分离和分析。     

微波辅助提取-气相色谱法同时测定中草药中有机磷和氨基甲酸酯农药残留

建立了中草药中有机磷和氨基甲酸酯类农药同时检测的气相色谱分析新方法.中药材试样依据正交实验的优化条件,用正己烷-丙酮(1∶4,V∶V)混合提取剂进行微波辅助提取,经弗罗里硅土和中性氧化铝混合层析柱净化后,采用HP-5毛细管柱分离,氮磷检测器同时检测中草药中15种有机磷和6种氨基甲酸酯类农药残留量.21种农药在0.01～1.0 mg/L的浓度范围内线性良好,线性相关系数为0.9950～1.000,检出限为0.002～0.01 mg/L.在0.05、0.2、0.5 mg/kg三个添加水平的平均回收率分别为75.11%～128.57%、75.85%～120.71%和76.43%～117.25%,相对标准偏差分别为 3.10%～10.58%、5.27%～9.94%和4.03%～9.03%.方法用于中草药中有机磷和氨基甲酸酯类农药残留的同时检测,结果良好.     

碳纤维超微盘电极的制备及对单囊泡胞吐动力学的高分辨研究

利用改良的电化学腐蚀方法制备了碳纤维超微盘状电极,具有方法简便,电极尺寸可控、可多次使用等优点.扫描电镜和伏安表征实验表明电极密封效果良好、电化学性能优良.在鼠嗜铬神经瘤PC12细胞上,用超微盘电极实现了高时空分辨、高保真度的单囊泡胞吐测定.与常规微电极相比,能更准确地反应囊泡融合这一超快过程(毫秒级)的动力学过程.     

Synthesis and Structure of(NH4)_2 [V2O_4(OCH_2COO)_2]

ＳｙｎｔｈｅｓｉｓａｎｄＳｔｒｕｃｔｕｒｅｏｆ（ＮＨ４）２［Ｖ２Ｏ４（ＯＣＨ２ＣＯＯ）２］ＺＨＯＵＺｈａｏ－ｈｕｉ，ＷＡＮＧＪｉｎｚｈｉ，ＷＡＮＨｕｉ－ｌｉｎａｎｄＴＳＡｌＫｈｉ－ｒｕｉ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，ＸｉａｍｅｎＵｎｉ...     

SYNTHESIS AND MESOMORPHIC PROPERTIES OF FISHBONE-LIKE LIQUID CRYSTALLINE POLYSILSESQUIOXANES——Ⅰ. FISHBONE-LIKE, β-DIKETONE-BASED LIQUID CRYSTALLINE POLYSILSESQUIOXANES AND THEIR COPPER COMPLEXES*

Two kinds of fishbone-like, β-diketone-based liquid crystalline polysilsesquioxanes(FBDKLCP'S), homopolymeric (H-FBDKLCP) and copolymeric (C-FBDKaLCP) have been first synthesized via the hydrosilylation reaction of a vinyl-terminated β-diketone with the homopolymeric ladderlike polyhydrosilsesquioxane (LPHSQ) and random copolymethylhydrosilsesquioxane (LRPMHSQ) respectively. These new kinds of FBDKLCP with M of 10~4 is thermotroic liquid crystalline polymer and its clearing temperatures T_i's and mesophase range △T's are much higher than those of the corresponding comb-like β-diketone liquid crystalline polysiloxane (DKLCP) by about 200℃. Similar results have been observed with the comparison of the two different structure Cu-coordinating compounds The significant increases in T_((?))'s and △T's of the FBDKLCP and Cu-FBDKLCP are mainly attributed to the great rigidity of the ladderlike polysilsesquioxane backbone.     

STUDIES ON ENHANCED CONDUCTIVITY OF STRETCHED CONDUCTING POLYMERS

A physical model of series of the conductivity on chain and the interchain conductivitybetween chains is proposed to explain enhanced conductivity of stretched conducting polymers.This model suggests that the enhanced conductivity for stretched conducting polymers might bedue to increasing of the interchain conductivity between chains along the elongation direction afterdrawing processes if the conductivity on chain is assumed much larger than that of the interchainconductivity between chains. According to this model, it is expected that the temperaturedependence of conductivity measured by four-probe method for stretched conducting polymers iscontrolled by a variation of the interchain conductivity between chains with temperature, whichcan be used to explain that a metallic temperature dependence of conductivity for stretchedconducting polymers is not observed although the conductivity along the elongation direction isenhanced by two or three orders of magnitude.