电沉积氧化铈对烧结镍电极性能的影响

在烧结镍基体表面，预先电沉积一层氧化铈，通过电化浸渍得到镍电极，研究了预先电沉积氧化铈对烧结镍电极性能的影响。结果表明：与空白烧结镍电极相比，预先电沉积氧化铈（＋4），改善了烧结镍电极的大电流充放电性能和循环性能，增加了电极的可逆性，提高了电极的充电接受能力和活性物质利用率，减少了电极膨胀率，且当氧化铈的预先电沉积量为5％时，烧结镍电极的电极性能处于最佳。     

聚吡咯修饰乳酸氧化酶电极的研制

根据聚吡咯修饰电极掺杂和去掺杂原理，将乳酸氧化酶固定在玻碳电极表面形成一种新型的乳酸酶电极，该电极灵敏度高，稳定性好，易于制作。本文报道了该电极的研制过程，探讨了影响电极响应的各种因素，找出了最佳实验条件。将此电极用于实际样品中乳酸含量的测定，结果令人满意。     

双极电极极化行为的模拟分析方法

在电化学工程中，常用一些具有三线结构的材料作为电极，如金属泡沫、碳纤维毡等．这种电极的优点是具有比平面（二维）电极大得多的电化学界面，常称三维电极·所谓双极三维电极是指在一种特殊状态下工作的三维电极：同一三维电极体的两侧分别发生阴极和阳极电极反应［‘，2］     

全固态锂离子选择性电极研究

研究了新型载体HPMBP-TOPO体系几种全固态锂离子选择性电极（涂丝电极、单层全固态电极、聚吡咯修饰层内接触电极）的性能。与传统型电极相比，固态电极响应斜率有所降低，而选择性稍有提高。其中聚吡咯修饰层内接触电极性能为最佳，该电极响应斜率为56.7mV/decade，并具有良好再现性和长期稳定性。     

一种适于高速充电的新型化学电源电极的研究

本文提出一种适于高速充电的新型化学电源电极，该电极体系在充电时，反应界面能迅速推移，使活性物质能迅速沉积在三维载体电极上，特别适用于强电流高速充电。充电时活性物质以固态沉积在电极表面，而放电时活性物质又溶解为液态。电极体系在充放电循环过程中活性物质是以固（态）－液（态）循环形式进行循环，因而可以保持新鲜的电极表面，防止固体电极表现活性物质的相变、脱落、变形等弊端，有利于延长电极的寿命，该电极体系可     

对插型阵列微带电极的制作及其电化学特性研究

用微电子光刻方法制作了对插型阵微带电极（ＩＤＡ），并通过ＳＥＭ对ＩＤＡ电极进行了表征，将微Ａｇ／ＡｇＣｌ参比电极和微铂丝对电极固定在ＩＤＡ电极附近，构成了微电解池，考察了该电极的循环伏安及计时电流特性，并用微带电极的扩散理论和Ｃｏｔｔｒｅｌｌ 公式对ＩＤＡ电极的准稳太电流进行了处理，指出了它们之间产生偏差的原因，研究了ＩＤＡ电极的“发生－收集”效应，测定了该电极的屏蔽因子、反馈因子和收集效率。     

纳米超微电极的研究（Ⅳ）—超微金柱电极的制作与表征

纳米超微电极的研究（Ⅳ）──超微金柱电极的制作与表征张学记，万其进，张悟铭，周性尧（武汉大学化学系，武汉，４３００７２）关键词微电极，纳米超微电极，伏安法，离子束，金纤维最近，纳米超微电极［１～５］的研制成功，使超微电极的研究进入一个新阶段，给电化学...     

曲率对管状电极电化学行为的影响

利用隐式差分法对管状电极对流扩散方程作了数值解，通过与平板电极电化学行为的比较，分析管状电极特性，讨论了曲率对管状电极电化学行为的影响，并给管状电极中使用Ｌｅｖｉｃｈ近似的条件。     

8—羟基喹啉合镁碳糊修饰电极的研究

本文研制了８－羟基喹啉合镁碳糊修饰电极，并研究了电极性能，实验发现，该修饰电极具有类化学传感器的特性，电极在一定条件下对Ｍｇ＾２＋离子有类能斯特响应，电极用于试样分析取得成功。     

1—（2—吡啶偶氮）—2—萘酚修饰的铅笔芯电极上铜的阳极溶出伏安特性

１引言我们曾用２Ｂ型铅笔芯制成电极并经实验证明它具有与玻碳电极类似的良好伏安特性。也曾用它作为基体电极，修饰８－羟基喹啉，研究了铜和锌的阳极溶出特性。本文研究了ｌ－（２－吡啶偶氮）－２－萘酚（ＰＡＮ）修饰的铅笔芯电极上铜的阳极溶出伏安特性，并用以测定了人发中的微量铜。探讨了铜在此电极上的预富集与溶出机理。２实验部分２．１仪器与试剂ＭＥＣ－１２Ａ型电化学分析仪，以ＰＡＮ修饰电极为工作电极，饱和甘汞电极为参比电极，铂电极为辅助电极，组成三电极体系。所有试剂均为分析纯试剂。水为二次去离子水。２．２电极…     

谈科学探究中的归纳与演绎

逻辑推理过程与事物的认识过程同时存在,科学探究离不开逻辑推理过程。归纳和演绎是认识过程中的两种逻辑推理形式,在学生的科学探究活动中,尤其是在提出问题、猜想与假设、设计实验方案与解释结论阶段,归纳和演绎发挥着重要的作用。本文重点论述了寻求现象原因的求异归纳推理、探寻化学物质通性及变化规律的不完全归纳推理、探求个别物质性质的演绎三段论、解释个别现象的演绎解释推理过程在科学探究中的重要作用。     

野生和种植翅果油树果实中微量元素的分析比较

采用火焰原子吸收光谱法对野生和种植翅果油树不同形状果实的果仁、果皮、果壳中Cu、Zn、Fe、Mg、Ca、K、Na、Mn 8种微量元素进行了分析比较.结果显示:在果仁果皮果壳中,8种微量元素的含量是K＞Mg＞Ca＞Fe＞Na＞Zn＞Mn＞Cu,其中果仁的Cu、Zn、Mg含量高.在果仁中Zn、Mg、K、Na、Mn是野生＞种...     

应用Diels-Alder反应制备聚合物的研究进展

由于Diels-Alder反应具有一系列重要特点(原子经济性、热可逆性、立体选择性、立体专一性和区域选择性等),自从1928年被发现以来,该反应就一直是人们研究的热点。将其应用于聚合物的合成中,可制备一些具有特殊性能的Diels-Alder聚合物,人们在这方面作了大量的研究工作,取得了许多研究成果。本文首先根据不同的分类标准,对应用Diels-Alder反应制备聚合物的研究进行了分类,然后结合本课题组的相关研究工作,综述了近年来人们在该领域的研究进展,最后展望了其研究前景。     

Analytical strategies to determine antibiotic residues in fish

The accelerated growth of aquaculture has resulted in a series of harmful effects to human health. The widespread and unrestricted use of antibiotics in this industry, to prevent bacterial infections, leads to remaining amounts in the aquatic environment. This has resulted in the emergence of antibiotic-resistant bacteria in aquaculture environments, in the increase in antibiotic resistance in fish pathogens as well as in the transfer of these resistance determinants to human pathogens. Moreover, the use of large amounts of antibiotics may lead to the presence of residual antibiotics in fish tissue and fish products. Fluoroquinolones, tetracyclines, penicillins, sulphonamides and other antibiotics, exhibiting activity against both Gram-positive and Gram-negative bacteria, are widely used for the treatment and prevention of diseases in fish. An extended and comprehensive review on the recent analytical methodologies concerning antibiotic residues in fish reported in the literature is provided in the present article. Emphasis is given on sample preparation regarding isolation and purification, chromatographic conditions and method validation according to legislation. Results of published assays are comparatively presented and criticised.     

青藏高原湖泊影响锂元素迁移和富集的矿物、元素及环境因素——以西藏郭扎错钻孔沉积物为例

作为我国战略性矿产的锂矿,主要赋存于青藏高原盐湖中。湖泊系统中,锂的富集和迁移规律关系到锂矿的高效提取和未来锂矿的储量估算。本文以西藏咸水湖郭扎错的钻孔沉积物为例,结合AMS14C年代和Mg元素含量变化,系统分析了孔隙水、碳酸盐矿物和硅酸盐矿物的锂含量变化,探讨了矿物、镁元素、环境变化和早期成岩作用等对锂元素迁移和富集的影响。郭扎错沉积物中锂和镁大部分存在于硅酸盐矿物中,锂和镁较高的相关性说明二者存在于相同的硅酸盐矿物中,如粘土矿物。大约90%的锂赋存在硅酸盐矿物中,约8.5%的锂赋存在碳酸盐矿物中,孔隙水中的锂含量占比仅约1.5%。碳酸盐矿物中Mg/Li摩尔比值为78–270,是孔隙水中10多倍,而硅酸盐矿物中的Mg/Li摩尔比值稳定在24–29之间。水–沉积物相互作用促进硅酸盐矿物中锂的释放,咸水环境下释放的锂多于淡水环境下。碳酸盐矿物中,锂和镁主要存在于方解石中。镁离子对锂离子的迁移具有阻碍作用,低温、高盐度下的阻碍作用更强。湖泊沉积物可能是湖水锂的一个重要来源。     

有机合成的“百宝箱”

20世纪所涌现的新试剂和新方法深刻地影响了有机合成的发展,其中很多开创性的成果获得了诺贝尔化学奖。这些试剂的结构不仅限于碳、氢、氧和氮这些有机合成中的基本元素,还扩充至元素周期表中其他元素。为了解这些碳、氢、氧和氮以外的元素在有机合成中的应用,本文以获得诺贝尔化学奖的有机化学相关成果为主要内容,对元素周期表中以硼、磷为代表的非金属,以锂、镁、铝为代表的主族金属,以及以钯为代表的过渡金属在有机合成中的应用作了简单梳理。     

石柱黄连及根际土壤中矿质元素特征分析

研究石柱黄连不同器官及其根际土壤中矿质元素特征,探究黄连根茎矿质元素间及其与土壤环境的相关性。采用电感耦合等离子体质谱法(ICP-MS)、电感耦合等离子体发射光谱法(ICP-OES)及原子荧光光谱法(AFS)测定了15组石柱黄连植株和根际土壤中18种矿质元素含量,所得数据运用SPSS 22.0统计软件分析。石柱黄连根际土壤中锰、磷、镁、镉、汞等元素含量的变异性较大,部分采样点土壤中镉含量超过农用地土壤污染风险筛选值。在检测的18种元素中,黄连植株中钙、镁、磷、钾含量最高,其次是铁、锰、锌,再次是锶、铜、镍,最后是铅、钒、钴、镉、钼、铬、砷、汞。须根对大部分矿质元素的富集能力强于根茎或地上部;黄连根茎对锌的富集能力强于须根或地上部;地上部对钙、磷、钾、铬的富集能力强于须根或根茎。Spearman分析表明黄连根茎矿质元素间、黄连根茎与土壤中矿质元素有一定相关性,部分具有统计学意义(P＜0.05)。石柱黄连不同器官中矿质元素含量有明显差异,以此建立的指纹图谱可用于区分黄连根茎及须根的粉末样品;黄连根茎中矿质元素间主要表现为协同作用,黄连根茎与土壤中矿质元素既有协同作用又有拮抗作用。     

Environmental aspects of tributyltin

The tributyltin species, the active ingredient in some antifouling paint formulations, is perhaps the most acutely toxic chemical to aquatic organisms ever deliberately introduced to water. It has been demonstrated to have an adverse effect on shellfish in France and England, and as a consequence the use of tributyltin-containing antifouling paints has been restricted in these countries. Other countries have banned the use of tributyltin-containing antifouling paints or are contemplating restrictions. This article reviews such environmental aspects of tributyltin as methods of analysis, toxicity, environmental occurrence, persistence and fate. Tributyltin concentrations in many locations may be high enough to cause chronic toxicity or harmful effects in some aquatic organisms, and in some locations the tributyltin concentrations may be high enough to be acutely toxic to some organisms. Biological degradation of tributyltin in water and sediment appears to be the most important factor limiting the persistence of tributyltin in aquatic environments. To some degree, then, the persistence of tributyltin in aquatic environments depends upon the nature of the ecosystem. Tributyltin exhibits low-to-medium persistence in water and moderate persistence in sediment. A summary is given of the regulatory status of tributyltin in some countries, and recommendations are made for further research.     

Effects of dilute acid and steam explosion pretreatments on the cellulose structure and kinetics of cellulosic fraction hydrolysis by dilute acids in lignocellulosic materials

Worldwide, yellows diseases impact plants important in human nutrition, the natural environment, and the culture and commerce of humans. Since the presumed pathogens, mycoplasma-like organisms (MLOs), have not been isolated in pure culture in vitro, their study must proceed by other experimental approaches. In a study of disease affecting grapevines in Europe and North America, polymerase chain reactions (PCR) and restriction analyses of PCR-amplified DNA were used to detect and differentiate strains of MLOs associated with grapevine yellows. MLOs were detected both in naturally diseased grapevines and in experimentally inoculated host plants. The data indicated an unexpected genomic diversity among grapevine-infecting MLOs, and supported their classification with MLOs in the aster yellows, X-disease, and elm yellows groups. The presence of diverse MLOs in grapevines provokes consideration that these MLOs may be present in overlapping geographic ranges and that multiple MLO infections may occur in individual plants, increasing the complexity of grapevine yellows epidemiology and control and the significance of sensitive MLO detection in planting stock and phytosanitary-regulated germplasm.     

Anion Recognition in Water: Recent Advances from a Supramolecular and Macromolecular Perspective

The recognition of anions in water remains a key challenge in modern supramolecular chemistry, and is essential if proposed applications in biological, medical, and environmental arenas that typically require aqueous conditions are to be achieved. However, synthetic anion receptors that operate in water have, in general, been the exception rather than the norm to date. Nevertheless, a significant step change towards routinely conducting anion recognition in water has been achieved in the past few years, and this Review highlights these approaches, with particular focus on controlling and using the hydrophobic effect, as well as more exotic interactions such as C?H hydrogen bonding and halogen bonding. We also look beyond the field of small‐molecule recognition into the macromolecular domain, covering recent advances in anion recognition based on biomolecules, polymers, and nanoparticles.