共查询到20条相似文献,搜索用时 593 毫秒
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针对无机化学传统教学模式的不足,构建了无机化学微信平台。介绍了构建平台必需的微信公众号和微信群的建立过程和方法。分析了无机化学微信平台在教学中的实践效果,弥补了传统教学中的不足。讨论了无机化学微信平台的积极作用,提高了教师教学水平和学生的学习能力,达到了师生双赢的目的。 相似文献
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基础化学实验室的建设与管理 总被引:2,自引:0,他引:2
化学实验室是全面完成化学教学任务的重要基地。 我院2002年建立了设备比较先进的化学实验室,给学生创造了良好的实验条件,并进行了科学化的管理,规定了各种规章制度和有关职责,较好地完成了化学教学任务。在实践中。采取:固定优秀代课教师兼管,勤工助学学生帮忙的管理办法,既减轻教师的劳动强度,又培养了学生的技能,且协调了各种关系,有利于化学教学质量的提高。 相似文献
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综述了海洋天然产物Diazonamide A全合成的研究进展,分析了各合成路线的关键步骤,讨论了各方法的特点。简单描述了Diazonamide A类似物构效关系的研究成果。参考文献17篇。 相似文献
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对纯镍及其表面离子注钇样品在1000℃空气中的恒温氧化和循环氧化行为进行了研究。用扫描电镜(SEM)和透射电镜(TEM)对氧化膜的表面形貌及结构进行了观测。研究表明离子注钇极大地提高了金属镍的抗氧化性能。此外,用声发射(AE)技术研究了氧化膜/基体界面上缺陷的分布情况,并用激光拉曼(Raman)谱对注钇引起的膜内应力变化进行了测量。结果表明,离子注钇降低了NiO氧化膜的生长速率,减小了表面NiO的晶粒尺寸,降低了膜内压应力水平。同时,离子注钇还减小了氧化膜/基体界面缺陷的平均尺寸和数目,因此,极大地提高了镍表面NiO氧化膜的粘附性和保护性。 相似文献
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苏教版教材中新增了大量鲜活有趣的实验探究活动,给学生提供了一个开展自主、探究、合作学习和自由展示操作能力及思维能力的平台。教学实践表明,这些实验活动大大激发了学生学习化学的自觉性和积极性。学生在探究活动中,开发了一些精彩的实验,展示了学生的创新思维和创造能力。 相似文献
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Influence of the spectral bandwith of the spectrometer on the sensitivity using continuum source AAS
Becker-Ross H Florek S Heitmann U Weisse R 《Analytical and bioanalytical chemistry》1996,355(3-4):300-303
The influence of the spectral bandwidth of the spectrometer on the performance of the spectrometer is of great importance in atomic absorption spectrometry using continuum source (CS-AAS). For a theoretical analysis of the detection of small absorbances two cases have to be taken into account: as long as the limiting noise of the signal is given by the detector noise an increase in spectral bandwidth of the spectrometer implies an improvement in the limit of detection. In contrast, if the noise of the signal is dominated by the photon shot noise the detection limit should become independent of the spectral bandwidth. In this case the spectral bandwidth of the spectrometer should be chosen equal to the bandwidth of the absorption line to avoid spectral interferences. Theoretical calculations are presented for the dependence of the characteristic mass on the spectral bandwidth in case of CS-AAS measurements. The results are compared with experimental measurements for six different elements using continuum source as well as line sources. The investigations were done using a double echelle monochromator (DEMON) which offers a high spectral resolution lambda/Deltalambda of about 140,000. 相似文献
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The apparent tendency, in recent literature concerned with the determination of chlorophylls, to ignore spectral bandwidth effects is critically discussed. Quantitative data are presented which allow the determination to be made with spectrophotometers of only moderate resolution. 相似文献
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Influence of the spectral bandwith of the spectrometer on the sensitivity using continuum source AAS 总被引:1,自引:0,他引:1
H. Becker-Roß S. Florek U. Heitmann R. Weiße 《Fresenius' Journal of Analytical Chemistry》1996,355(3-4):300-303
The influence of the spectral bandwidth of the spectrometer on the performance of the spectrometer is of great importance in atomic absorption spectrometry using continuum source (CS-AAS). For a theoretical analysis of the detection of small absorbances two cases have to be taken into account: as long as the limiting noise of the signal is given by the detector noise an increase in spectral bandwidth of the spectrometer implies an improvement in the limit of detection. In contrast, if the noise of the signal is dominated by the photon shot noise the detection limit should become independent of the spectral bandwidth. In this case the spectral bandwidth of the spectrometer should be chosen equal to the bandwidth of the absorption line to avoid spectral interferences. Theoretical calculations are presented for the dependence of the characteristic mass on the spectral bandwidth in case of CS-AAS measurements. The results are compared with experimental measurements for six different elements using continuum source as well as line sources. The investigations were done using a double echelle monochromator (DEMON) which offers a high spectral resolution / of about 140,000. 相似文献
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R.E. Craig 《Photochemistry and photobiology》1964,3(3):189-194
Abstract— The physical units most commonly used in photometry have limited value outside the field of illumination engineering. They tend also to conceal rather than display the physical concept of radiation as understood at present.Only by making the concepts of quantum theory accessible by a fundamental change of units, can those concepts make their full contribution to photobiology.
The paper suggests adoption of the quantum as the unit of intensity and the electron volt as the specification of spectral quality, thus bringing the nomenclature of photometry into line with other branches of radiation physics. A start is made with definition of some of the essential derived units, source intensity, irradiation, and flux. 相似文献
The paper suggests adoption of the quantum as the unit of intensity and the electron volt as the specification of spectral quality, thus bringing the nomenclature of photometry into line with other branches of radiation physics. A start is made with definition of some of the essential derived units, source intensity, irradiation, and flux. 相似文献
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Z Chi B M Cullum D L Stokes J Mobley G H Miller M R Hajaligol T Vo-Dinh 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2001,57(7):1377-1384
In this work, we present the fluorescence spectra of anthracene and pyrene vapors at different elevated temperatures (from 150 to 650 degrees C) excited with the 337 nm line of a nitrogen laser. We describe the high temperature effects on the resulting spectral properties including spectral intensity, spectral bandwidth and spectral shift. We found that the PAH fluorescence spectral bandwidths become very broad as the temperature increases. The broadening is mainly due to thermal vibrational sequence congestion. We also have found that the fluorescence intensity of pyrene vapor increases with increasing temperature, which results from the increase of the pyrene vapor absorption cross section at 337 nm. 相似文献
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研究了电感耦合等离子体原子发射光谱法(ICP-AES)快速测定铁镍软磁合金中的镍含量,确定了最佳测定条件,以波长221.647nm作为镍的分析线,对溶解酸和酸浓度的影响进行探讨,选择钇作为内标元素。分析试样得到结果的相对标准偏差RSD小于0.91%(n=6),方法回收率为99.8%~100.1%(n=6),分析结果与丁二酮肟分光光度法相一致。电感耦合等离子体原子发射光谱法比传统的化学法准确、快速,已成功用于生产中。 相似文献
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研究了电感耦合等离子体原子发射光谱法(ICP-AES)快速测定铁镍软磁合金中的镍含量,确定了最佳测定条件,以波长221.647nm作为镍的分析线,对溶解酸和酸浓度的影响进行探讨,选择钇作为内标元素。分析试样得到结果的相对标准偏差RSD小于0.91%(n=6),方法回收率为99.8%~100.1%(n=6),分析结果与丁二酮肟分光光度法相一致。电感耦合等离子体原子发射光谱法比传统的化学法准确、快速,已成功用于生产中。 相似文献
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Abstract We have used a flashlamp driven tunable dye laser as a radiation source for observing UV-C and UV-B action spectra of two eukaryotic microorganisms. The general nature of the irradiation system and various operating parameters are described. The laser produces the high power output required for UV-B action spectroscopy; it is tunable throughout the UV-B range with the very narrow bandwidth required for high resolution action spectra. The peak power density does not appear to reach the threshold of 'two photon' biological effects, a concern when using pulsed lasers for action spectroscopy. The laser is somewhat more expensive and considerably more difficult to operate compared with arc-monochrometer systems; it is generally equal or greater in UV-B power and has distinct advantages in tunability and bandwidth of the spectral output. 相似文献
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痕量铜的光度法分析进展 总被引:14,自引:0,他引:14
综述了近年来测定痕量铜的光度法,包括常规光度法、流动注射光度法、导数光度法、析相光度法、催化动力学光度法、萃取光度法、荧光光度法、原子吸收光度法等。 相似文献