算盘文化中的诗和画

算盘是我国古代的一项重大发明，可与印刷、造纸、火药和指南针四大发明相提并论。英国学者李约瑟称“算盘是中国的第五大发明”。算盘在中国古代社会，广泛运用于社会生活的各个领域，影响巨大，并且以算盘为中心形成了丰富的算盘文化。本文着重论述在算盘文化中，算盘诗和算盘画是其重要组成部分，值得研究和弘扬。     

超声萃取-高效液相色谱法同时测定纺织固体废物中17种含氯苯酚化合物

建立了测定纺织固体废物中17种含氯苯酚化合物的高效液相色谱(HPLC)分析方法.以甲醇为萃取溶剂,超声萃取纺织固体废物样品中的含氯苯酚化合物,经蒸发浓缩和定容后,HPLC法测定,外标法定量.结果 表明,以甲醇为萃取溶剂,萃取温度40℃,萃取时间30 min时,萃取效果最佳.在筛选的实验条件下,17种含氯苯酚化合物在1～...     

Determination of Potassium Ferrocyanide in Foods by Resonance Rayleigh Scattering Method with Double-Charged Triaminotriphenylmethane Dyes

In pH 1.0 acidic medium, double-charged triaminotriphenylmethane dyes such as methyl green （MEG） and iodine green （IG） react with potassium ferrocyanide to form 2 ： 1 ion-association complexes by virtue of electrostatic forces and hydrophobic interaction. It results in the change of absorption and the great enhancement of resonance Rayleigh scattering （RRS） and the appearance of new RRS spectra. Two systems have similar spectral characteristics and their maximum RRS wavelengths are all located at 276 nm and smaller peaks are located at 332 and 457 nm, respectively. The intensity of RRS is directly proportional to the concentration of [Fe（CN）6]^4- in the range of 0.03-5.7 μg·mL^-1 （MeG system） or 0.04-5.9 μg·mL^-1 （IG system）. The RRS method has high sensitivity and the detection limit （3σ） for potassium ferrocyanide is 9.3 ng·mL^-1 （MeG system） or 11.2 ng·mL^-1 （IG system）. The optimum conditions, influencing factors and effects of foreign substances are investigated. The method also has a good selectivity. A sensitive, rapid and simple RRS method for the determination of potassium ferrocyanide in salinized food and table salt has been developed.     

用某些双电荷三氨基三苯甲烷染料共振瑞利散射法测定食品中的亚铁氰化钾

在pH 1左右的酸性介质中，甲基绿（MeG）和碘绿（IG）双电荷三氨基三苯甲烷染料与亚铁氰根阴离子能借助静电引力和疏水作用而形成2：1的离子缔合物，在引起吸收光谱变化的同时，能导致共振瑞利散射（RRS）的显著增强，并出现新的RRS光谱，两体系有相似的RRS光谱特征，最大RRS波长位于276 nm，并在332 nm，457 nm有强度较低的散射峰，K₄[Fe(CN)₆]分别为0.03~5.7μg•mL^-1(MeG体系)和0.04~5.9μg•mL^-1(IG体系)范围内，K₄[Fe(CN)₆]浓度与散射强度(ΔI_RRS)成正比。方法具有高灵敏度，对K₄[Fe(CN)₆]的检出限(3σ)分别为9.3 ng•mL^-1和11.2ng•mL^-1。本文实验了适宜的反应条件和影响因素，考察了共存物质的影响，表明方法有较好的选择性，可用于盐渍食品和食盐中痕量亚铁氰化钾的测定。     

滂胺天蓝共振瑞利散射法测定穿琥宁

在pH4.5的酸性溶液中,取适量穿琥宁溶液和滂胺天蓝溶液混合,以二次蒸馏水稀释,放置一段时间后在荧光光度计上以λem=λex方式进行同步扫描;滂胺天蓝和穿琥宁能够迅速反应生成离子缔合物,导致共振瑞利散射（RRS）光谱的改变,产生较特征的、新的RRS光谱,最大峰值在717.5nm处,并且在35—95mg/L范围内,RRS强度和穿琥宁的浓度成正比;由此建立了测定穿琥宁的共振瑞利散射法。     

共振瑞利散射法测定盐渍食品中的亚铁氰化钾

1引言研究发现,在弱酸性介质中,当Fe(Ⅲ)与亚铁氰化钾反应生成普鲁士蓝时,在引起吸收光谱变化的同时,将导致共振瑞利散射(RRS)的显著增强,其最大散射波长在316nm,它不仅是灵敏度高,检出限达4.36μg/L,远远高于分光光度法(检出限为1mg/L),而且有色盐渍食品本身的颜色不产生共振瑞利散射,因此不干扰测定。从而解决了盐渍食品本身颜色对分光光度法测定亚铁氰化钾的困扰。据此提出了一种灵敏度高、选择性好、而且简便快速的RRS法。2实验部分2.1仪器与试剂F-2500型荧光分光光度计(日本岛津公司),狭缝宽度10nm;UV-8500型紫外-可见分光光度计(…     

稀土离子对微生物Hormesis效应机制的研究进展

稀土离子生物活性的研究始于20世纪初,研究表明稀土离子对微生物具有广泛的"低促高抑"现象,即Hormesis效应。就稀土离子对微生物产生Hormesis效应的可能机制进行了综述,其中包括稀土离子对生物膜、核酸分子以及酶分子作用,以期为更好地理解稀土离子与微生物的相互作用、扩展稀土离子在微生物育种方面的应用提供参考。     

多金属物体CT图像的金属伪影校正

针对多金属伪影的校正问题,本文通过仿真实验分析了多金属伪影的成因,并提出了一种基于投影校正的多金属伪影校正方法.该方法首先直接从投影域分割出金属区域,然后建立对金属区域投影值的校正模型,最后通过调整模型参数达到校正目的.模型以重建图像的灰度熵为目标函数,采用单纯形法迭代求解使熵最小时的校正参数.仿真和实际数据的实验结果表明,本文算法对多金属伪影的校正起到了良好的效果,且校正后的图像质量优于插值校正法.     

Dynamical investigation and parameter stability region analysis of a flywheel energy storage system in charging mode

In this paper, the dynamic behavior analysis of the electromechanical coupling characteristics of a flywheel energy storage system （FESS） with a permanent magnet （PM） brushless direct-current （DC） motor （BLDCM） is studied. The Hopf bifurcation theory and nonlinear methods are used to investigate the generation process and mechanism of the coupled dynamic behavior for the average current controlled FESS in the charging mode. First, the universal nonlinear dynamic model of the FESS based on the BLDCM is derived. Then, for a 0.01 kWh/1.6 kW FESS platform in the Key Laboratory of the Smart Grid at Tianjin University, the phase trajectory of the FESS from a stable state towards chaos is presented using numerical and stroboscopic methods, and all dynamic behaviors of the system in this process are captured. The characteristics of the low-frequency oscillation and the mechanism of the Hopf bifurcation are investigated based on the Routh stability criterion and nonlinear dynamic theory. It is shown that the Hopf bifurcation is directly due to the loss of control over the inductor current, which is caused by the system control parameters exceeding certain ranges. This coupling nonlinear process of the FESS affects the stability of the motor running and the efficiency of energy transfer. In this paper, we investigate into the effects of control parameter change on the stability and the stability regions of these parameters based on the averaged-model approach. Furthermore, the effect of the quantization error in the digital control system is considered to modify the stability regions of the control parameters. Finally, these theoretical results are verified through platform experiments.