共查询到20条相似文献,搜索用时 62 毫秒
2.
3.
Hydrogen is the most abundant chemical element in the Universe and is tightly related to human life. This article personifies hydrogen, bringing a close interaction between the hydrogen on the moon and the hydrogen on the Earth. Through lively and interesting dialogues, the history of hydrogen discovery and the properties are introduced, and the application of hydrogen in different aspects of the future is prospected. 相似文献
4.
"PBL"教学法在"有机合成"教学中的运用 总被引:5,自引:0,他引:5
为突破传统教学模式,提高有机化学教学质量,本文尝试在“有机化学”课程的“有机合成”部分采用“PBL”教学法模式,取得了较好的效果。“PBL”教学法是以问题为基础的教学方法,它能拓展知识面,联系不同学科中的相关知识点,加强了学生学习的主动性,训练了学生的思维能力,让知识永久的存储于学生的记忆中,使教学处于融洽的氛围中。 相似文献
5.
《燃料化学学报》1960,(1)
Pa3BIjTHe llal〕叩Horo xo一、只neTBa H nPe水八e BeeroT只水e几。仑”H八yeTI〕”Ir B IJaeTo月山eef;I飞eM只I王eMbre几HMo 6e3 nP”MeHeHH只ra3a. ra3“B几分eTe只HaxI6溯eey八o6H助M H 3RoHo卜飞uqH以MB”八oM Ton刀HBa,a TaK水eeblPbeM八几分x”MHqeeKo仑nPoM曰nJ涯eHHoe丁H.Hen即b3oBa朋e ra3a B nPoM曰川刀eHHoeTI卫3Ha,IH咒涯bHo HHTeHeH中且双HPyeT nPoH3Bo八eTBeHH曰e nPo找eeeH,noB仗山aeT日P洲3Bo八HTe月b-HOCTb H KyJIbTyPy TPy八a,y几yq班aeT caHHTaPHO一川rHeHHqeCRHe y… 相似文献
6.
"问题米"、"问题面" 总被引:2,自引:0,他引:2
近闻广东、广西、海南等南方城市先后发现“问题米”、“问题面”而引起食物中毒的事件。其中广东省卫生、公安、工商等部门联合采取行动,查“问题米”近百吨;广西玉林5所学校因食用“问题面”一次中毒竟达400余名学生。就此卫生部立即通告全国,要求各地对辖区的大米、麦面生产经营单位进行 相似文献
7.
《分析测试技术与仪器》2010,(4):252-252
仪器信息网”耗材”和”配件”栏目在紧锣密鼓的筹备工作之后,终于全新上线,这2个栏目汇聚了国内外近600家仪器常用配件耗材生产商和供应商信息以及50万条产品信息.如实验过程中常用的色谱柱、氘灯、传感器等仪器零配件;玻璃器皿、化学试剂和标准物品等实验耗材,都可以在这2个栏目中找到并询价. 相似文献
8.
原子量是最为基础的科学概念之一,"国际纯粹与应用化学联合会(IUPAC)"之"同位素丰度和原子量委员会(CIAAW)"每两年会修订并发布一次原子量。自2009年起,IUPAC宣布某些元素的原子量不再是常数,这些元素的标准原子量为区间值。为方便使用,对于这些元素,给出一个合理的单一数值,称为常规原子量。何为标准原子量?何为常规原子量?为何某些元素的原子量出现区间值?依据原子量数值的特性,元素可以分为几大类?本文在介绍最新元素周期表中原子量的特点之后,简述原子量测定、标准确定、概念演变的发展历史,讨论原子量的修订与变化等问题。 相似文献
9.
10.
11.
The syntheses of 3β-hydroxy-5β-carda-14, 20:22-dienolide (= «β»-anhydro-), 3β-hydroxy-5β-carda-8:14, 20:22-dienolide (= «α»-anhydro-) and «δ»-anhydro-digitoxigenin (= probably 3β-hydroxy-5β, 14β-carda-8, 20:22-dienolide) by the best ways known to date, have been described. «δ»-Anhydro-digitoxigenin represents the thermodynamically most stable isomer. In this isomer the double bond in position 8 is unaffected by hydrogenation with Pt in acetic acid; with perbenzoic acid an epoxide results from which, on hydrogenation, the double bond can be regenerated in its original position. Analogous reactions are known to occur in the 8:14-epoxides. 相似文献
12.
Chemistry is a central, practical and creative discipline. The development of chemistry plays an important role in the progress of science and society, as well as the improvement of the quality of human life. This paper introduces the chemical knowledge of stone, concrete, glass and other inorganic nonmetallic building materials by the anthropomorphically story. Taking nanomaterials as an example, the prospect of building materials development in the future is put forward. 相似文献
13.
Chemical probes are valuable tools for the investigation of biochemical processes, diagnosis of disease markers, detection of hazardous compounds, and other purposes. Therefore, the development of chemical probes continues to grow through various approaches with different disciplines and design strategies. Fluorescent probes have received much attention because they are sensitive and easy-to-operate, in general. To realize desired selectivity toward a given analyte, the recognition site of a fluorescent probe is designed in such a way to maximize the binding interactions, usually through weak molecular forces such as hydrogen bonding, toward the analyte over other competing ones. In addition to such a supramolecular approach, the development of fluorescent probes that sense analytes through chemical reactions has witnessed its usefulness for achieving high selectivity, in many cases, superior to that obtainable by the supramolecular approach. Creative incorporations of the reactive groups to latent fluorophores have provided novel chemical probes for various analytes. In this feature article, we overview the recent progress in the development of turn-on fluorescent probes that are operating through chemical reactions triggered by target analytes. Various chemical reactions have been implemented in the development of many reactive probes with very high selectivity and sensitivity toward target analytes. A major emphasis has been focused on the type of chemical reactions utilized, with the hope that further explorations can be made with new chemical reactions to develop reactive probes useful for various applications. 相似文献
14.
Scott RT Milios CJ Vinslava A Lifford D Parsons S Wernsdorfer W Christou G Brechin EK 《Dalton transactions (Cambridge, England : 2003)》2006,(26):3161-3163
[Mn(IV)Mn(II)3] triangular units directed by the presence of tripodal alcohols self-assemble in the presence of azide and acetate ligands to form either a [Mn24] "wheel" or a [Mn32] "cube". 相似文献
15.
Opsteen JA Brinkhuis RP Teeuwen RL Löwik DW van Hest JC 《Chemical communications (Cambridge, England)》2007,(30):3136-3138
Polymersomes, composed of amphiphilic polystyrene-block-poly(acrylic acid) (PS-b-PAA), with the periphery being covered with azide groups, were used for further functionalization using "click" chemistry. 相似文献
17.
18.
19.
20.