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11.
Kritsana Jitmanee Jaroon Jakmunee Somchai Lapanantnoppakhun Sunanta Wangkarn Norio Teshima Tadao Sakai Gary D. Christian Kate Grudpan 《Microchemical Journal》2007,86(2):195-203
Derivative techniques for analytical signal processing are useful for solving some noise and signal resolution problems in various fields of study such as titrimetry, spectrophotometry, chromatography and electrochemistry. The broad use of these techniques, however, is often limited by costly inflexible built-in software packages in commercial analytical instruments. We propose here the application of commercial simple software packages such as Microsoft® Excel and Microcal Origin for signal smoothing and fitting, and for obtaining derivative analytical signals in batch and flow-based analyses, including potentiometric titration, spectrophotometry, chromatography, voltammetry and sequential injection analysis (SIA). The worldwide (especially Excel) software packages are easy-to-use for less experienced users and have also capabilities for advanced users, and therefore employing such packages can result in expansion of useful derivative techniques. We demonstrate application of the available package-aided derivative capabilities for enhancing some chemical analyses, including potentiometric acid–base titration, Bradford assay of protein, chromatographic separation of ajmaline and reserpine and anodic stripping voltammetry of copper. The derivative signals from smoothed and fitted curves offer better accuracy and precision, even for non-resolving peaks and tailing peaks. In some cases, the optimization of experimental conditions is not further required, which can lead to fast method development. 相似文献
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Yupeng Xing Xiaoke Wang Shuhua Hao Xueli Zhang Xiao Wang Wenxuan Ma Gang Zhao Xijin Xu 《中国化学快报》2021,32(1):13-20
g-C3N4 have been widely used in the fields of photocatalytic hydrogen production,photocatalytic degradation of dyes and oxidative degradation of toxic gases due to their excellent performance.It has attracted extensive attention in recent years due to its highly efficient photocatalytic capacity of hydrogen generation,water oxidation,carbon dioxide reduction and degradation of organic pollutants.Because of the abundant carbon and nitrogen composition of the earth,large-scale production and industrial applications of this material are possible.The modification of this material makes its performance more excellent so that this new material can obtain a steady stream of vitality.These outstanding works have become important materials and milestones on the road to mankind's photocatalytic hydrogen production.This review will begin with the basic idea of designing,synthesizing and improving g-C3N4 based photocatalytic materials,and introduce the latest development of g-C3N4 photocatalysts in hydrogen production from four aspects of controlling the carbon/nitrogen ratio,morphology,element doping and heterojunction structure of g-C3N4 materials. 相似文献
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西藏羊八井位于东经90.53°, 北纬30.11°, 海拔4310m, 垂直地磁截止刚度14.1GV. 2005年1月20日羊八井太阳中子望远镜和中子监测器探测到与X7.1/2b太阳耀斑相关的GLE事件, 其中太阳中子望远镜能量>40MeV的能道在5min(07:00—07:05UT)和20min(07:00—07:20UT)的时间间隔内计数率增长的统计显著性分别是3.7σ和6.0σ, 同时羊八井中子监测器也探测到计数率的增长,初始时间为06:51—06:52UT. 观测表明在这次GLE事件中太阳质子可被加速到能量大于10GeV. 相似文献
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The fluorescence property of xTbF3-BaF2-AlF3-GeO2+ySmF3 (x=0.01-40 mol%, y=0-5 wt%) glasses were investigated. The enhancement of Sm3+ fluorescence was recognized in the presence of Tb3+. Increasing Tb3+ content, the emission color changed from green to orange. When the intensity of fluorescence at 540 nm originated from Tb3+ is compared with that at 600 nm originated from Sm3+, the information about the concentration quenching of Tb3+ and Sm3+ was obtained. From these results, rare earth ions were dispersed identically in the glasses. After heating to 673 K or cooling to 77 K, the emission color of 20TbF3-20BaF2-10AlF3-50GeO2/mol%+0.05 wt% SmF3 glass was reversibly changed from orange to green. In addition, while the emission from 10TbF3-20BaF2-10AlF3-60GeO2+0.01 wt% SmF3 glass was green, its crystallized sample, prepared by annealing at 1073 K, exhibited an orange emission due to Sm3+ at room temperature. 相似文献
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Prader-Willi syndrome (PWS) is a multisystem disorder caused by DNA abnormalities involving chromosome 15. Major characteristics are infant hypotonia, hypogonadism, mental retardation, a short stature, atypical facial appearance, and the onset of obesity due to insatiable hunger in early childhood. Also, speech and language abnormalities have been reported including voice disorders. These have seldom been studied in detail, however. This paper reports the results of an acoustic and aerodynamic investigation of the voice in 22 individuals with PWS. Two age groups were distinguished, a group of children [chronological age (CA) 6 years, 7 months through 11 years, 7 months; total intelligence quotient (TIQ) 40-88] and a group of adolescents and adults (CA 17 years, 1 month through 29 years, 5 months; TIQ 41-94). Both aerodynamic and acoustic parameters were obtained and compared with normative data from the Belgian Study Group on Voice Disorders. It was found that voice difficulties do commonly occur in individuals with PWS including impairment of frequency levels, voice quality, and poor aerodynamic capabilities. 相似文献
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<正>Metal-enhanced room temperature phosphorescence of diiodofluorescein was first observed on filter paper surface.The phosphorescence intensity is 2.5-fold brighter from diiodofluorescein on silver nanoparticles-deposited filter paper as compared with an identical control sample without silver nanoparticles.Furthermore,enhanced absorption was also observed for the same system.Our findings suggest that both singlet and triplet states can couple to surface plasmons and enhance phosphorescence quantum yields at room temperature,as well as to increase the excitation rate of lumophores at room temperature. 相似文献
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Fluorescence spectroscopic properties of the complex formation between six new C-pivot16-crown-5 ethers bearing fluorescence side arms and metal ions are studied. Six new C-pivot 16-crown-5 ethers that carry fluorescence side arms were synthesized. The research also included the examination of different fluorescent behavior of the new lariat ethers in the presence of silver and sodium ions (Ag+ and Na+) in methanol. Because of the good fit of the cavity size of these 16-crown-5 ethers with the Ag+ and Na+ ions, remarkable change in fluorescent spectra were observed. The results showed that the new lariat crown ethers exhibited enhanced selectivity towards sodium ion, but silver ion show quenching abilities towards the ligands. Cooperative participations of the C-pivot side arm oxygen with the ring oxygen molecules in complexation was also confirmed by the single crystal X-ray crystallography of the complex, (C27H30O7)·NaClO4. The freezing of crown ring conformation and the diminishment of the chance of sidearm oscillation that occurred upon complexation with sodium ion are the main causes of fluorescent enhancement. The quenching caused by the addition of silver ion was found to explainable by the photo-induced electron transfer that results in the reduction of silver ions. 相似文献