TTA氧化发光反应的研究及应用

本文研究了TTA-H_2O_2-ClO~-新体系的化学发光行为,对影响化学发光强度的诸因素进行了实验和讨论,还探讨了该化学发光反应的分析应用.     

铁氰化钾—过氧化氢氧化鲁米诺发光的研究及应用

研究了铁氰化钾-过氧化氢氧化鲁米诺化学发光行为,依据铜对该化学发光反应的抑制作用,建立了微量钢的化学发光测定法,该法要出限为2.5×10~(-10)g/ml,线性范围为1.0×10~(-9)～1.0×10~(-5)mg/L.此方法已成功地用于实际水样中微量铜的测定.     

表面活性剂在化学发光反应中的作用

数种表面活性剂对鲁米诺-H_2O_2-Fe~(3+),光泽精H:O。AllO和2,9一二甲基一1,IG菲咯琳一H:O。-Cu’”三种化学发光反应的影响情况进行了试验研究,对表面活性剂在化学发光反应中的作用及机理进行了初步讨论.     

超微弱化学发光体系的研究及应用

随着科技的发展,在近几年,人们对过氧化氢以及无机盐在结合中所产生的超微弱化学发光体系的研究越来越多。本文阐述了超微弱化学发光体系的研究现状,从而得知该体系的反应条件比其它化学物品要温和,并且具有高选择性,可以为开发新型化学发光试剂提供相应的理论基础。     

水体样本重金属离子检测方法探究

水体重金属离子污染主要是指重金属离子污染物进入水体后对水体所造成的污染。重金属离子主要来源于工业废水,冶炼、化工、电子等工业生产所产生的废水中均含有一定量的重金属离子。若未对重金属废水进行有效处理,就直接排放到自然水体当中,会给生态环境、食物链及人类健康带来严重危害。基于此,本文对水体样本重金属离子检测方法进行了综合性阐述,以供参考。     

除去聚芳醚酮中金属离子的方法

聚芳醚酮通常采用亲电反应或者亲核反应聚合合成。然而在制备的过程中,发现聚芳醚酮中存在大量来自催化剂残留金属离子。残留的金属离子会导致聚合物的热稳定性能、耐化学性能、机械强度、绝缘变差。本文介绍了减少聚合物中的金属离子的一些方法。     

人血清中微量铜的化学发光法测定

基于Cu~(2+)对鲁米诺-MnO_4~-化学发光反应的抑制作用建立了血清铜含量的化学发光分析法.测定铜(Ⅰ)的检出限为8.6×10~(-9)/ml,线性范围为1.0×10~(-8)～2.0×10~(-6)g/ml;对含1.0×10~(-7)g/ml cu~(+2)的水溶液进行10次重复测定,其结果的变异系数为4.3％.将本法应用于人血清中铜含量的测定,结果满意。     

水环境化学中金属离子的规范表示

对涉及水环境化学的部分期刊中文章题名与正文中金属离子的表达形式进行了调查,结果表明: 金属离子的表达形式多种多样,如二价态铜离子主要有“铜”(或“Cu”)、“铜离子”(或“Cu离子”)、“Cu²⁺”、“铜(II)”(或“Cu(II)”)等表达形式,且76%以上用Cu²⁺表示。由于水环境中大多数金属离子的存在形式多种,因此,除了专门研究金属离子各种形式的情形之外,水环境化学中研究的金属离子一般都是指某价态所有形式的该金属离子,通用规范的表达形式应是用价态(以罗马数     

自激荧光在污染水体中轻重金属离子检测研究

受污染水体中很少存在单一的污染源,导致污染水体中混合污染源难以确定与区分。研究一种在多污染源中各种金属离子的确定和检测问题。提出了采用自激荧光对受污染水体进行检测,对污染物中混有轻重金属的污染水体分别检测,对重金属污染物采用紫外光谱吸收与荧光光谱吸收检测,对轻金属污染物自激荧光光谱检测。形成了活泼金属离子的检测与治理方法,通过分析自激荧光在猝灭过程中产生的特殊光谱特性来进行不同污染物种的金属离子判断,采用紫外光对重金属离子进行二次判断,以达到快速检测的目标。实验结果表明,检测方法能有效检测污染水体中的各金属离子,对受污染水体的判断具有较好的指导性。     

CMC聚合物对重金属离子的吸附性能

通过正交试验得出制备羧甲基纤维素(CMC)聚合物的最佳工艺条件:丙烯酸(AA)/羧甲基纤维素=10,引发剂(硫酸铵)和交联剂(N,N'-亚甲基双丙烯酰胺)用量分别为单体的0.0014倍和0.0015倍.吸胀平衡后,将CMC聚合物在400~450℃下完全灰化16h,消解并用火焰原子吸收法测定聚合物对Zn2+、Cu2+、Pb2+、Cd2+、Cr2+、Ni2+和Mn2+的吸附性能.结果表明,CMC聚合物对重金属离子具有一定的吸附能力,其吸附量随着溶液pH值和重金属离子质量浓度的增加而增大,当pH为9时达到最大;并且CMC聚合物对Pb2+和Cu2+的吸附量要大于其他金属离子.     

Dissolution-precipitation growth of uniform and clean two dimensional transition metal dichalcogenides

Two dimensional transition metal dichalcogenides (TMDCs) have attracted much interest and shown promise in many applications. However, it is challenging to obtain uniform TMDCs with clean surfaces, because of the difficulties in controlling the way the reactants are supplied to the reaction in the current chemical vapor deposition growth process. Here, we report a new growth approach called ‘dissolution-precipitation’ (DP) growth, where the metal sources are sealed inside glass substrates to control their feeding to the reaction. Noteworthy, the diffusion of metal source inside glass to its surface provides a uniform metal source on the glass surface, and restricts the TMDC growth to only a surface reaction while eliminating unwanted gas-phase reaction. This feature gives rise to highly uniform monolayer TMDCs with a clean surface on centimeter-scale substrates. The DP growth works well for a large variety of TMDCs and their alloys, providing a solid foundation for the controlled growth of clean TMDCs by the fine control of the metal source.     

Hierarchically porous monoliths based on low-valence transition metal (Cu,Co, Mn) oxides: gelation and phase separation

Hierarchically porous monoliths based on copper (Cu), cobalt (Co) and manganese (Mn) oxides with three-dimensionally (3D) interconnected macropores and open nanopores were prepared using metal bromides as precursors via a sol–gel process accompanied by phase separation. The difficulty of gelation for low-valence metal cation was overcome by introducing a highly electronegative Br atom near to the metal atom to control the rates of hydrolysis and polycondensation. The 3D interconnected macropores were obtained using appropriate polymers to induce phase separation. The domain sizes of macropores and skeletons can be controlled by reaction parameters such as concentration and/or average molecular weight of polymers, and the amount of hydrochloric acid. The crystalline metal oxide monoliths with their 3D interconnected macroporous structure preserved were obtained after heat treatment in air.     

高氟氯锌氧粉综合回收价金属的研究

改进高氟氯锌氧粉回收有价金属工艺流程,通过实验得到低酸浸出液固比、反应时间、酸度及温度等较佳工艺条件,有效的回收高氟氯锌氧粉中锌、铟等物质,达到废弃物综合利用目的。     

硒催化羰基化反应若干进展

采用廉价的催化剂代替昂贵的金属,低成本的一氧化碳代替氢气乃至光气,一直是人们追求的目标.综述了非金属硒在含碳、氮、氧、硫类有机化合物中的催化羰基化反应,以及在Se/CO/H2 O体系中一些有机化合物的高选择性还原反应,介绍了近期的一些新进展.催化剂量的硒在温和条件下,即可活化一氧化碳而直接进行羰基化和还原反应,特别是发展了将硝基化合物的还原羰基化与胺的氧化羰基化相结合,合成一系列精细化学品和生物化学品.催化剂硒在催化反应中表现出反应过程相转移的特性,兼具了多相催化与均相催化的优点,是反应过程相转移概念中的典型实例.硒催化反应的特点是反应物转化率高,反应选择性专一,原子经济性高,对环境友好,且可部分替代光气合成法     

水溶性树脂交联剂的合成

水溶性树脂作为聚合物的交联剂,广泛的应用在油田堵水调剖作业。本试验以苯酚和糠醛为实验原料,对水溶性树脂交联剂的生产工艺进行优化。研究结果表明：在碱金属为催化剂的条件下,以苯酚：糠醛（物质的量）=1：2.3进行反应,在70℃的下持续反应4小时,可以促使苯环上的邻、对位都进行羟甲基化反应,合成水溶性树脂交联剂。     

Zn/Cd超富集植物天蓝遏蓝菜(Thlaspi caerulescens)中TcCaM2基因的克隆及在酵母中的重金属耐受性分析

从重金属超富集植物天蓝遏蓝菜(T. caerulescens)Cd胁迫的cDNA文库中，通过基因表达的差异筛选得到的阳性克隆之一，核苷酸序列分析表明与拟南芥CaM2的相似性高达92%，故命名为TcCaM2(T. caerulescens CaM2, GenBank No. EF053035)。其核苷酸序列与迄今已知的钙调蛋白基因同源率在83%以上，其氨基酸序列同源性高达95%以上，与大多数高等植物的CaM，如印度芥菜、拟南芥、水稻等同源性则更高。将TcCaM2基因置于酵母表达启动子之下，构建酵母表达载体，并将其转入重金属敏感型酵母突变菌株，酵母重金属耐受实验表明，TcCaM2在酵母中的过量表达提高了酵母对Co2+或Ni2+的耐受性，增加了对Cd2+的敏感性，对Zn2+胁迫抗性稍有增加但差异不显著；说明TcCaM2通过其对重金属离子的结合作用及在信号转导系统中的功能，在植物细胞对重金属的富集、耐性中发挥了重要的调节作用。     

Spatial decoupling of light absorption and reaction sites in n-Si photocathodes for solar water splitting

Metal-insulator-semiconductor (MIS) photocathodes offer a simple alternative to p-n junction photocathodes in photoelectrochemical water splitting. However, the parasitic light absorption of catalysts and metal layers in the MIS junction, as well as the lack of low work function metals to form a large band offset with p-Si, severely limit their performance. This paper describes an MIS photocathode fabricated from n-Si, rather than the commonly used p-Si, to spatially decouple light absorption from reaction sites, which enables the majority carriers, instead of the commonly used minority carriers, to drive the surface reaction, making it possible to place the reaction sites far away from the light absorption region. Thus, the catalysts could be moved to the backside of the MIS junction to avoid light shielding. Moreover, the adoption of n-Si unlocks a variety of high work function materials for photovoltage generation. The obtained n-Si MIS photocathode exhibits an applied bias photon-to-current efficiency of 10.26% with a stability up to 300 h.     

浅谈元音的应用

元极学认为，音是世界的本质，以元极音乐贯通人的身心以及实验对象，是元极科研的重要这一，许多实验证明，以元极音乐贯通，能促成水稻增产，可使金属铸件抗拉强度，断面收缩率均得以提高，对化学振荡反应的振幅，周期，寿命等均产生影响。     

Thermodynamic analysis and kinetic optimization of high-energy batteries based on multi-electron reactions

Multi-electron reaction can be regarded as an effective way of building high-energy systems (>500 W h kg⁻¹). However, some confusions hinder the development of multi-electron mechanisms, such as clear concept, complex reaction, material design and electrolyte optimization and full-cell fabrication. Therefore, this review discusses the basic theories and application bottlenecks of multi-electron mechanisms from the view of thermodynamic and dynamic principles. In future, high-energy batteries, metal anodes and multi-electron cathodes are promising electrode materials with high theoretical capacity and high output voltage. While the primary issue for the multi-electron transfer process is sluggish kinetics, which may be caused by multiple ionic migration, large ionic radius, high reaction energy barrier, low electron conductivity, poor structural stability, etc., it is urgent that feasible and versatile modification methods are summarized and new inspiration proposed in order to break through kinetic constraints. Finally, the remaining challenges and future research directions are revealed in detail, involving the search for high-energy systems, compatibility of full cells, cost control, etc.     

Partially hydroxylated ultrathin iridium nanosheets as efficient electrocatalysts for water splitting

Ultrathin two-dimensional (2D) materials have attracted considerable attention for their unique physicochemical properties and promising applications; however, preparation of freestanding ultrathin 2D noble metal remains a significant challenge. Here, for the first time, we report use of a wet-chemical method to synthesize partially hydroxylated ultrathin Ir nanosheets (Ir-NSs) of only five to six atomic layers’ thickness. Detailed analysis indicates that the growth confinement effect of carbon monoxide and the partially hydroxylated surface play a critical role in formation of the ultrathin structure. The ultrathin Ir-NSs exhibit excellent performance for both the hydrogen evolution reaction and oxygen evolution reaction in a wide pH range, outperforming the state-of-the-art Pt/C and IrO₂, respectively. Density-functional theory calculations reveal that the partial hydroxylation not only enhances the surface electron transfer between Ir-sites and intermediate O-species, but also guarantees efficient initial activation of bond cleavage of H-O-H for first-step H₂O splitting. This, ultimately, breaks through barriers to full water splitting, with efficient electron transfer essentially maintained.