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1.
本文提出了一种基于"沾笔"纳米刻蚀和电化学还原技术在表面上制备金属及半导体纳米结构的普适性方法.用这种方法可以在硅表面直接书写线宽度低于50纳米的多种金属和半导体组成的纳米结构.这种简单而有效的方法在精确控制位置和结构的功能化纳米器件制备中具有重要的潜在应用前景.  相似文献   

2.
对7种含"单"或"双"吡唑啉化合物在溶液和在固体器件[ITO/TPD/TPBI-2%EP/TPBI/Mg-Ag]中作为掺杂发光材料的电致发光特性进行了研究.结果表明,由吡唑啉化合物所构成的器件具有优良的电致发光特性.特别是在5-位处联有芳基的双吡唑啉化合物,由于它们具有良好的成膜能力和较高的玻璃化转变温度,因此所制得的器件有很好的稳定性.结果还表明,含双吡唑啉基化合物的荧光量子产率较含单吡唑啉基者为低.由它们所构成器件的电致发光能力也大体反映出相同的趋势.  相似文献   

3.
"点击化学"是指在Cu(Ⅰ)离子的催化作用下,端基炔和叠氮化合物之间的1,3-环加成反应.自从2001年被发现以来,点击反应已用于多种化合物的合成制备~([1,2]).该反应的条件十分温和,甚至在pH7的水溶液中、室温条件下即可进行.此外,该反应还具有高选择性、高效率、高稳定性以及良好的生物兼容性,因而在生物分子的共价标记方面具有重要的应用前景.目前,点击反应不仅用于离体状态下生物分子的标记,而且还成功用于活体肿瘤细胞的靶向检测~([3]).  相似文献   

4.
徐春芸 《化学教育》2011,32(7):50-51,59
电子杂志,又称网络杂志、互动杂志,是一种非常好的媒体表现形式.它将图像、文字、声音、视频、游戏等相互动态结合来呈现给读者,此外,还有超链接、及时互动等网络元素.教师可以利用电子杂志来促进学生的学习.iebook超级精灵是一款电子杂志制作软件,操作简单方便,可协助软件使用者轻松制作出集高清视频、音频、Flash动画、图文等多媒体效果于一体的电子杂志.笔者在人教版九年级化学第四单元课题3"离子"的教学中,应用iebook超级精灵制作电子杂志,促进学生学习.  相似文献   

5.
吕琳  王佳  吴星  许竹青 《化学教育》2011,32(4):35-37
研究了"适当分块策略"的内涵,并以化学概念教学为载体,对该策略的使用效果进行了研究.结果显示,该策略具有减轻学生学习负担、提高化学学习效率的作用,且对女生和中等学业成绩的学生影响尤为显著.  相似文献   

6.
采用"分段"转化为"完整"G-四链体脱氧核糖核酸酶的策略,构建了检测多聚核苷激酶(T4 PNK)的传感器.将形成G-四链体的富G序列PS5.M序列拆分成5 '和3'端均为羟基的两条链:链S1OH和链S2OH,即分别具有12个碱基的"分段"的PS5.M.在ATP存在下,T4 PNK酶可以将链S2OH的5 '端的羟基磷酸化,转化为S2P;在S1OH、S2P以及Helper链S—H存在下,T4 DNA连接酶(T4 DNA Ligase)将链S1OH和链S2P连接成"完整"的PS5.M序列.在体系中再加入核酸外切酶Ⅲ(ExoⅢ),从S—H的3'端剪切S-H,释放出PS5.M.在K+存在下,PS5.M与氯化血红素(Hemin)作用,形成具有类过氧化物酶活性的复合物,催化H2O2氧化2,2'-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐(ABTS)的反应,通过检测氧化产物在418 nm处的吸收值变化,实现对T4 PNK活性的定量检测.线性检测范围为0.02 ~ 3.0 U/mL,检出限为0.014 U/mL(S/N=3).对Hela细胞和HEK293细胞实际样本的T4 PNK活性进行了检测,平均回收率为95.6%~105.7%.  相似文献   

7.
针对现有医用有机化学实验课程教学内容单一、教学模式传统、实验学时不足、学生重视程度不够等问题,构建了基于"虚实结合"的医用有机化学实验混合教学模式,主要包括教学方法变更、教学内容丰富、虚拟仿真实验引入、课程考核体系完善.实践发现,混合教学模式的应用更好地培养了学生自主创新的实践能力,为实践课程教育改革提供了有效依据,同时,让实践教学以时时、处处、人人皆可学的"新形态"展现在学生面前.  相似文献   

8.
朱敬华 《化学教育》2003,24(7):64-65
实验是化学教师的基本授课手段,是培养学生形成科学的思维方式、掌握科学的研究方法的有效途径.实验教学中如何既重"技能训练",又要突出"创新能力的培养"?我认为,关键是要在化学实验教学中把握好"度"与"导",下面就其中的艺术谈谈自己的认识.  相似文献   

9.
赵华  高峰 《化学教育》2011,32(3):42-45
"化学反应原理"的内容具有研究对象的复杂性和关联性、研究层次的多样性和交错性、研究方法的综合性和实用性等.化学反应原理学习的难点集中、学习兴趣影响因素众多以及教学和教材缺乏多元化,是导致原理学习困难的主要因素.探查原理学习的策略发现,联系策略、引申拓展策略、概括组织策略及分析递归策略在信息处理的不同阶段发挥着重要作用....  相似文献   

10.
采用糖球模板法结合热致相分离技术,制备了孔径尺寸、内连通度及孔隙率高度可控的左旋聚乳酸(PLLA)支架材料,并通过扫描电镜(SEM)、红外光谱(FTIR)以及示差扫描量热法(DSC)对其空间结构及性能进行了系统研究.支架材料孔径从50μm到800μm及内连通孔径从10μm到200μm连续可调,微观孔壁结构根据不同溶剂可形成各异的微纳米结构.支架的制备对PLLA化学结构无显著影响,但相分离过程会不同程度地降低PLLA的结晶度.  相似文献   

11.
12.
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   

13.
Yanyun Li  Shaowei Tao 《大学化学》1986,35(11):144-149
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   

14.
15.
[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   

16.
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   

17.
'Decoking' of a 'coked' zeolite catalyst in a glow discharge in oxygen is investigated. The 'decoking' process involves reactions of atomic oxygen (O atoms) with 'coke' and yields gases such as CO, CO2 as well as other gaseous products that could be easily pumped out.Three different modes of discharge were investigated including a static mode, a flowing-gas mode, and a periodic-purge mode where the oxygen and other gaseous products of the discharge were replaced by fresh O2 gas after short but regular intervals of time. In some cases, additional heating was also used to provide base temperatures of the order of 100 °C to facilitate penetration of oxygen atoms into the inner layers and cages of the zeolite catalyst.This paper presents some results of spectroscopic analytical techniques used to monitor the atomization of oxygen, oxidation of 'coke', and to confirm the process of 'decoking'. More specifically, radiation emission on the 3 s 5S– 3p 5P transitions of O around 777.2–777.5 nm were selected for monitoring the atomization of O2. On the other hand, X-ray photo-electron spectroscopy (XPS) was used to determine the amount of residual carbon and extent of 'decoking'. Furthermore, evolution of CO and CO2 gases as a function of time was systematically monitored in real time. For CO, the 451.1 nm band head belonging to the B1 - A1 bands of the Angstrom system of the CO spectrum was used, while for CO2, the band head at 353.4 nm belonging to the CO2+ spectrum was used. The rates of evolution of CO and CO2 were related to the rate of 'decoking' of the catalyst. It is noted that in the periodic-purge mode, about 63% of the total yield of CO from a given sample of the catalyst appears in the first 3-min exposure to discharge whereas it takes up to 15 min to remove nearly 94% of the removable carbon under our experimental conditions.  相似文献   

18.
With its tailored learning content, flexible learning environment and directed teacher guidance, the flipped classroom in "nutrition chemistry" has effectively solved the problems of students' specialty, large number and limited time in the course of elective course. The teaching mode based on the cultivation of students' ability and the core of improving scientific literacy was constructed.  相似文献   

19.
胡亚东 《化学通报》2003,66(8):507-508
哲学家和物理学家都喜欢研究和讨论“时间” ,时间之矢告诉人们光阴冉冉不复返 ,矢者失也。然而人们却总想回忆 ,寻找那些美好的或沮丧的过去 ,是安慰或自娱吧。我一直相信生活总是向前的 ,社会总是进步的 ,就和宇宙不停地膨胀一样。《化学通报》复刊已经 3 0年了 ,既然是复刊 ,必然先有停刊。历史总是把破坏和重建放在一起考虑的 ,才能找出规律。人们都说 2 0世纪是自然科学大发达的时代 ,然而 2 0世纪又是人类社会灾难最多的时代。正因如此 ,才促使科学多极化地、多样性地发展起来 ,从欧洲到美洲到亚洲 ,一点点 ,慢慢地扩散开来 ,也许 ,真…  相似文献   

20.
A study on static polarizabilities for a family of gold clusters (Au(n), n = 6, 12, 20, 34, 54) is presented. For each cluster, a density functional theory perturbation theory calculation was performed to compute the cluster polarizability and the polarizability of each atom in the cluster using Bader's "quantum theory of atoms in molecules" formalism. The cluster polarizability tensor, α(cluster), is expressed as a sum of the atom-in-molecule tensors, α(cluster)=∑(Ω)α(Ω). A strong quadratic correlation (R(2) = 0.98) in the isotropic polarizability of atoms in the cluster and their distance to the cluster center of mass was observed. The cluster polarizabilities are in agreement with previous calculations.  相似文献   

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