专业英语期中作业

专业英语期中作业

10级化学三班 201001010333 李倩

1．From Elements to Clusters: The Periodic Table Revisited

Virtuallyeveryonewhohasbeenexposedtoascienti?csubject has heard the name “Mendeleev”, the individual credited with devising the periodic law. Concepts leading to the periodic table1 canbetracedtoanumberofearlyobservations,amongthe

?rstbeingcuriousrelationshipsbetweenthemolecularweightsof various compounds determined by a German chemist, Johann Doebereiner (Goethe’s chemistry teacher). His ?ndings, which predatedMendeleev’sdiscoverybysome50years,wereaprelude to the periodicity noted. Prior to J. J. Thomson’s discovery of the electron, all of the observations were based on atomic weights and the occasional discovery of numerous elements whose weights or properties ?t the periodic relationships based on Mendeleev’s predictions.

2.Ag(I) N-Heterocyclic Carbene Complexes: Synthesis, Structure, and Application

N-Heterocyclic carbenes have received a great deal of attention within the last 15 years. They have been investigated for several purposes but are most promi- nent in the field of catalysis. The development of N-heterocyclic carbene complexes of silver has mainly come about by the discovery of the transmetalation from silver NHCs to other metal NHC systems. Silver N-heterocyclic carbenes, unlike other metal NHC systems, can be synthesized without the need for anaerobic conditions. The ease with which silver NHCs can be synthesized and undergo transmeta- lation has made it and continues to make it the most attractive route in the development of many metal NHC systems.

The structural study of silver NHCs has led to a diverse field of bonding motifs in the solid state. The silver-carbene interaction remains, in general, con- sistent from one bonding motif to another. The only exception to this is when the N-heterocyclic carbene bridges two silver cations. Argentophillic and silver- halide interactions play key roles in the formation of the structurally diverse silver NHC chemistry. The restraints of the ligand, sterics and flexibility (for multidentate ligands), are also factors that determine the outcome of the reaction. However, more study needs to be done to establish the rel- evance of these potential catalysts.

3. Metal/N-Heterocyclic Carbene Complexes: Opportunities for the Development of Anticancer Metallodrugs

Metal-NHCs affect mitochondria by inhibiting TrxT and other proteins. The possibility of using novel azolium precursors and various metals should offer interesting perspectives for the rapid and selective construction of libraries of high molecular diversity and complexity, and could be achieved by pre-[9a] or post- functionalization[9b–e] synthetic paths or by using the auto functionalization of CuI-NHCs bearing azides,[9f] thus provid- ing a basis for the design and development of metal-based drugs associated with unprecedented biological targets. 4.GOLD-TREE

Eucalyptus trees may translocate Au from mineral deposits and support the use of vegetation (biogeochemical) sampling in mineral exploration, particularly where thick sediments dom- inate. However, biogeochemistry has not been routinely adopted partly because biotic mechanisms of Au migration are poorly understood. For example, although Au has been previously measured in plant samples, there has been doubt as to whether it was truly absorbed rather than merely adsorbed on the plant surface as aeolian contamination. Here we show the ?rst evidence of particulate Au

within natural specimens of living biological tissue (not from laboratory experimentation). This observation conclusively demonstrates active biogeochemical adsorption of Au and provides insight into its behaviour in natural samples. The con?rmation of biogeochemical adsorption of Au, and of a link with abiotic processes, promotes con?dence in an emerging technique that may lead to future exploration success and maintain continuity of supply. 科学家最初发现，生长在地下约35米处存在金矿的土壤中的桉树，其叶片上的金元素浓度，比生长在800米外的桉树叶片高20倍。研究人员也已证实，树实际上是从土壤中吸收金属，并最终沉积到叶片上。但这一研究并不适合所有地区，植物探矿也需进一步实践研究。 5.气溶胶

气溶胶是悬浮在大气中固体粒子或液态小滴物质的统称。

雾、烟、霾、霭和烟雾等，都是天然的或人为的原因造成的大气气溶胶。 6. 2013年诺贝尔化学奖

2013年诺贝尔化学奖被授予了美国科学家马丁?卡普拉斯、迈克尔?莱维特、阿里耶?瓦谢尔，以表彰他们“在开发多尺度复杂化学系统模型方面所做的贡献”。

在三位获奖者的研究中，他们将便于计算化学反应过程、但只适于小分子的量子物理学和计算简单且能为大分子建模、但无法模拟化学反应的经典物理学结合在一起，建立了一种多尺度复杂化学系统模型。三位化学家所做的研究工作为今天的研究工作奠定了坚实的基础，帮助人们加深了对化学过程的理解和预测。 7.抗体---药物偶联剂（ADCs）的研究进展

抗体---药物偶联剂（ADCs）将基于抗体的免疫疗法与基于化学药物的化学疗法结合在一起，充分协同发挥抗体药物和化学药物各自的优点，利用抗体对靶细胞的特异性结合能力，输送对癌细胞具有高度杀伤效力的小分子高细胞毒性化学药物，以此来实现对癌变细胞的有效杀伤。 8.荧光探针

使用荧光染料溶液如Ardrox、Basic Yellow 40或罗丹明6G（Rhodamine 6G）作为着色剂，与邻苯二醛一起和蛋白质或氨基酸发生反应，产生高荧光性物质，从而使不易被肉眼观察到的物象清晰的显现出来。这一研究适用于众多的刑事调查中，用来帮助警察找出潜伏的指纹，协助案件的调查侦破。 9.化学元素周期表

化学元素周期表中，重点讲解了有关重金属的内容。所谓重金属是指密度在4.5g/cm3以上的金属。原子序数从23(V)至92(U)的天然金属元素有60种，除其中的6种外，其余54种的相对密度都大于4.5g/cm3，因此从相对密度的意义上讲，这54种金属都是重金属。

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但是真正划入重金属的金属元素有：铜、铅、锌、锡、镍、钴、锑、汞、镉和铋及U。

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其中铝、汞、铅及U对人体伤害很大，在日常生活中应尽量避免这些重金属的摄入，

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尤其要远离极具辐射性的U。

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