Kinetic Spectrophotometric Determination of Trace Titanium(Ⅳ) Based on Oxidation Discoloration of Acid Chrome Blue K with Hydrogen Peroxide

A simple and sensitive kinetic spectrophotometric method for the determination of trace amounts of titanium(IV),based upon the catalytic effect of Ti(IV) on the oxidation of acid chrome blue K (ACBK) by hydrogen peroxide in 0.002 mol/L sulfuric acid,is described. The reaction rate is monitored spectrophotometrically by measuring the decrease in absorbance of ACBK at 524 nm. The detection limit of the method is 1.01×10?9 g/mL,and the linear range is 0-0.048 mg/L. The influence of acidity,concentration of reactants,reaction time,reaction temperature and for-eign ions is also discussed. The optimum reaction conditions were established and some kinetic parameters determined. The apparent activation energy of the catalytic reaction is 5.32 kJ/mol. The relative standard deviation for the determi-nation of titanium(IV) at the concentration of 0.048 mg/L is calculated to be 1.31% (n = 11). In combination with sol-vent extraction separation,the method has been successfully applied to the determination of trace titanium(IV) in human hair,plant matter,tea and rock samples. The results are in good agreement with the certified values with the relative standard deviations (RSD) of 1.4%-3.5%.

Effects of Regulation of C/N Ratio Wheat Straw Application on Nitrogen,Phosphorus and Potassium Uptake in Tobacco

[Objective]The aim was to study the effects of regulation of C/N ratio wheat straw application on tobacco nitrogen,phosphorus and potassium uptake. [Method]Effects of regulation C/N ratio wheat straw application on the flue-cured tobacco yield,output value,nitrogen,phosphorus and potassium content and cumulative uptake of the upper,middle and bottom leaf were studied by using the field plot experiments at Banqiao town,Qujing city,Yunnan Province during the 2008-2009 summer growing seasons. [Result]The results showed that the application of wheat straw alone or after C/N regulation,could significantly increase tobacco production,potassium content,the potassium and nitrogen accumulation amount of leaf,and was more conducive to the potassium uptake of tobacco leaf with wheat straw application after C/N regulation. Compared with non-straw application,the yield of tobacco increased by 6.59%,3.58%,5.98%,8.80% with application of wheat straw alone,wheat straw and vetch,wheat straw and oilseed cake,wheat straw and urea nitrogen,the potassium content in tobacco leaf increased by 3.85%,7.76%,8.82%,11.21%,respectively,the total potassium cumulative amount of leaf increased by 10.71%,11.62%,15.32% ,21.01% and the total nitrogen cumulative amount increased by 9.76%,1.22%,8.14%,14.00%. However,the differences of tobacco leaf nitrogen content among the different treatments were not significant,the phosphorus uptake of tobacco leaf decreased. [Conclusion]application of high C/N ratio wheat straw in flue-cured tobacco production,which should be concerned not only to adjust C/N ratio by adding nitrogen,but also considering additional phosphorus application.

Application of derivative ratio spectrophotometry for determination of β-carotene and astaxanthin from Phaffia rhodozyma extract

A derivative ratio spectrophotometric method was used for the simultaneous determination of β-carotene and astaxanthin produced from Phaffia rhodozyma. Absorbencies of a series of the standard carotenoids in the range of 441 nm to 490 nm demonstrated that their absorptive spectra accorded with Beer’s law and that the additivity when the concentrations of β-carotene and astaxanthin and their mixture were within the range of 0 to 5 μg/ml, 0 to 6 μg/ml, and 0 to 6 μg/ml, respectively. When the wavelength interval (?λ) at 2 nm was selected to calculate the first derivative ratio spectra values, the first derivative amplitudes at 461 nm and 466 nm were suitable for quantitatively determining β-carotene and astaxanthin, respectively. Effect of divisor on derivative ratio spectra could be neglected; any concentration used as divisor in range of 1.0 to 4.0 μg/ml is ideal for calculating the derivative ratio spectra values of the two carotenoids. Calibration graphs were established for β-carotene within 0?6.0 μg/ml and for astaxanthin within 0?5.0 μg/ml with their corresponding regressive equations in: y=?0.0082x?0.0002 and y=0.0146x?0.0006, respectively. R-square values in excess of 0.999 indicated the good linearity of the calibration graphs. Sample recovery rates were found satisfactory (>99%) with relative standard deviations (RSD) of less than 5%. This method was suc- cessfully applied to simultaneous determination of β-carotene and astaxanthin in the laboratory-prepared mixtures and the extract from the Phaffia rhodozyma culture.

Identification of Rice Accessions Associated with K+/Na+ Ratio and Salt Tolerance Based on Physiological and Molecular Responses

The key for rice plant survival under Na Cl salt stress is maintaining a high K^+/Na^+ ratio in its cells. Selection for salt tolerance rice genotypes based on phenotypic performance alone will delay in progress in breeding. Use of molecular markers in tandem with physiological studies will help in better identification of salt tolerant rice accessions. Eight rice accessions along with the check Dongjin were screened using 1/2 Yoshida solution with 50 mmol/L NaCl at the seedling stage. The accessions IT001158, IT246674, IT260533 and IT291341 were classified as salt tolerant based on their K^+/Na^+ ratios. Seventeen SSR markers reported to be associated with K^+/Na^+ ratio were used to screen the accessions. Five SSR markers(RM8053, RM345, RM318, RM253 and RM7075) could differentiate accessions classified based on their K^+/Na^+ ratios. Banding pattern of the accessions was scored compared to the banding pattern of Dongjin. The study differentiated accessions based on their association of K^+/Na^+ ratio with molecular markers which are very reliable. These markers can play a significant role in screening large set of rice germplasms for salt tolerance and also help in identification of high-yielding varieties with better salt tolerance. The salt tolerant accessions can be taken forward into developing better varieties by conventional breeding and exploring genes for salt tolerance.

Phase Structure, Microstructure and Electrical Properties of K_xNa_((1-x))NbO_3 Piezoelectric Ceramics with Different K/Na Ratio

The K_xNa_((1-x))NbO_3(x=0.45, 0.46, 0.47, 0.48, 0.49, 0.50) lead-free piezoelectric ceramics was fabricated by conventional solid-state sintering method. It was found that the ratio of alkaline metal would affect the microstructure, bulk density, and optimum sintering temperatures of ceramics. Meanwhile, the electrical properties were also influenced by modulating the K/Na ratio, exhibiting corresponding composition-dependent properties. The optimum electrical properties of K_xNa_((1-x))NbO_3 such as piezoelectric constant d_(33) = 115 pC/N, mechanical quality factor Q_m = 20, Curie temperature Tc = 365 ~oC, ε_(33)~T/ε_0= 588.1, dielectric loss tan δ = 0.024, bulk density(ρ) = 3.08 g/cm^3, remnant polarization(P_r) = 8.87 μC/cm^2 and coercive field(Ec) = 13.79 kV/cm were obtained at x = 0.46.

Preparation of Layered Potassium Titanate Whiskers with Large Length-diameter Ratio by KDC Method

Pure K2Ti4O9 whiskers were prepared by KDC（Kneading-Drying-Calcination） method with TiO2 and K2CO3 as raw materials. The influences of TiO2/K2CO3 molar ratio（RT/K）, calcination temperature（TC） and cooling process on phase composition and morphology of the whiskers were investigated by TG-DSC（thermo gravimetric-differential scanning calorimeter）, XRD（X-ray diffraction）, and SEM（scanning electron microscope）. Pure K2Ti4O9 potassium titanate whiskers with large length-diameter ratio（r）（over 250） can be obtained at RT/K = 2.9 and TC = 950 ℃.

Effect of various Na/K ratios in low-salinity well water on growth performance and physiological response of Pacific white shrimp Litopenaeus vannamei

To investigate the influence of sodium to potassium （Na/IO ratios on the growth performance and physiological response of the Pacific white shrimp （Litopenaeus vananmei）, various concentrations of KC1 were added to low-salinity well water （salinity 4） in an 8-week culture trial. Six treatments with NWK ratios of 60：1, 42：1, 33：1, 23：1, 17：1, and 14：1 were replicated in triplicate. The highest weight-gain rate （3 506±48）% and survival rate （89.38±0.88）% was observed in well water with Na/K ratios of 23：1 and 42：1, respectively, while the feed conversion ratio （1.02～0.01）, oxygen consumption, and ammonia-N excretion rate was the lowest in the medium with a Na/K ratio of 23：1. Gill Na＋-K＋-ATPase activity, as an indicator of osmoregulation, peaked in the treatment where the Na/K ratio was 17：1. The total hemocyte count, respiratory burst, and immune-related enzyme activities （ALP, LSZ, PO, and SOD） ofL. vananmei were affected significantly by Na/K ratios （P〈0.05）. After challenged with Vibrio harveyi, the cumulative mortality of shrimp reared in a Na/K ratio of 23：1 （30±14.14）% was significantly lower than the control （75～7.07）%. In conclusion, the addition of K＋ to low-salinity well water in L. vannamei cultures is feasible. Na/K ratios ranging from 23：1 to 33：1 might improve survival and growth. Immunity and disease resistance are also closely related to the Na/K ratio of the low-salinity well water. The findings may contribute to the development of more efficient K^＋ remediation strategies for L. vananmei culture in low-salinity well water.

Influence of Chemical Effect on the Kβ/Kα Intensity Ratios and Kβ Energy Shift of Co, Ni, Cu, and Zn Complexes

Chemical effects on the Kβ/Kα intensity ratios and △E energy differences for Co, Ni, Cu, and Zn complexes were investigated. The samples were excited by 59.5 keV γ-rays from a ^241Am annular radioactive source. K X-rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. We observed the effects of different ligands on the Kβ/Kα intensity ratios and △E energy differences for Co, Ni, Cu, and Zn complexes. We tried to investigate chemical effects on central atoms using the behaviors of different ligands in these complexes. The experimental values of Kβ/Kα were compared with the theoretical and other experimental values of pure Co, Ni, Cu, and Zn.

Ratio K: a New Way of Metering and Evaluating the Risk and Return of Stock Investment

Although widely used, both the Markowitz model and VAR (Value at Risk) model have some limitations in evaluating the risk and return of stock investment. By the analysis of the conceptions of risk and return, together with the three hypotheses of technological analysis, a novelty model of metering and evaluating the risk and return of stock investment is established. The major indicator of this model , risk-return ratio K, combines the characteristic indicators of risk and return. Regardless of the form of the risk-return probability density functions, this indicator K can always reflect the risk-return performances of the invested stocks clearly and accurately. How to use the model to make optimum investment and how to make portfolio combined with clustering analysis is also explained.

Application of A New Spectrophotometric Method Manipulating Ratio Spectra for Determination of Bambuterol Hydrochloride in the Presence of Its Degradation Product Terbutaline

A simple,specific,accurate and precise spectrophotometric stability indicating method is developed for determination of bambuterol hydrochloride(BH)in the presence of its degradation product terbutaline(TERB)and in pharmaceutical formulations.A newly developed spectrophotometric method called ratio difference method by measuring the difference in amplitudes between 245 and 260nm of ratio spectra.The calibration curves are linear over the concentration range of 0.1~1mg·mL-1 for BH and 0.1~0.7mg·mL-1 for TERB with mean percentage recovery of 100.56±0.751 and 99.88±1.183,respectively.The selectivity of the proposed method is checked using laboratory prepared mixtures.The proposed method has been successfully applied to the analysis of BH in pharmaceutical dosage forms without interference from other dosage form additives and the results have been statistically compared with pharmacopeial method.

A Comparative Study of the Novel Ratio Difference Method versus Conventional Spectrophotometric Techniques for the Analysis of Binary Mixture with Overlapped Spectra

The smart novel ratio difference spectrophotometric method was developed and validated for the determination of a binary mixture of Sodium cromoglicate (SCG) and Fluorometholone (FLU) in presence of benzalkonium chloride without prior separation. The results were compared to that of the conventional methods (dual wavelength and first derivative of ratio spectra). The suggested methods were validated in compliance with the ICH guidelines and were successfully applied for determination of SCG and FLU in their laboratory prepared mixtures and commercial ophthalmic solution. The novel method showed significant advantages over the conventional methods regarding simplicity, minimal data manipulation and maximum reproducibility and robustness;which enabled the analysis of binary mixtures with overlapped spectra for routine quality control testing with quite satisfactory.

激光雷达反演消光系数的k值确定方法

利用济阳国家基本气象站1550 nm米散射激光雷达观测数据,对反演气溶胶消光系数过程中k值的确定方法进行了初步研究.基于雷达原始信噪比信号,利用Klett法反演得到气溶胶消光系数,训练建立气溶胶消光系数神经网络预测模型.使用模型得到当前时刻气溶胶消光系数预测值,反推计算k值.使用得到的k值反演气溶胶消光系数,并与使用能见度数据计算的气溶胶消光系数对比分析,相关系数达到0.920,气溶胶消光系数反演效果得到明显提升.

15W@80K全气体轴承室温活塞脉管制冷机研发

为了满足超大规格线列、面阵红外探测器及红外光学系统对大冷量、长寿命、低振动、紧凑化、高效率及轻型低温制冷机的需求,开展了15 W@80 K全气体轴承室温活塞脉管制冷机研发,采用Sage热力学软件进行了仿真分析,设计了首款基于全气体轴承支撑和室温活塞功回收技术的斯特林脉管制冷机,成功完成了工程样机研制并进行了性能测试。测试结果表明,散热流体温度20℃,制冷温度为80 K,制冷机在交流输入功率为320 W时,制冷量达到22 W,制冷效率达到6.875%;输入电功为397.9 W时,制冷量达到26.16 W,制冷效率为6.56%,冷量质量比(制冷量/质量)为3.1W/kg。散热流体温度20℃,制冷温度为60 K,制冷机在交流输入功率为360 W时,制冷量达到14 W,制冷效率为3.91%;制冷机在交流输入功率为400 W时,制冷量达到15.46 W,制冷效率为3.86%。验证了室温活塞调相技术的先进性,样机性能参数满足项目技术指标要求。

以偶氮胂K光度法测定蛋白质

研究了偶氮胂Ｋ（Ａｒｓｅｎａｚｏ Ｋ） 与蛋白质的反应及利用此反应测定蛋白质的最佳实验条件。 偶氮胂Ｋ 与蛋白质生成的复合物的最大吸收波长为６１１ ｎｍ ， 比偶氮胂Ｋ 红移７１ ｎｍ ， 对照性好。 在室温下， 于ｐＨ ２．８ ～３ ．９的缓冲溶液中， 反应迅速完成。 表面活性剂Ｔｒｉｔｏｎ Ｘ－ １００ 和溴化十六烷基吡啶（ＣＰＢ） 均可提高反应的灵敏度，复合物稳定， 干扰少。 绘制了牛血清白蛋白（ＢＳＡ） 、γ－ 球蛋白（ γ＿Ｇ） 、人血清白蛋白（ ＨＡＳ） 、血红蛋白（Ｈｂ） 、卵白蛋白（ ＯＶＡ） 、溶菌酶（Ｌｙｓｏ） 、胃蛋白酶（Ｐｅｐ） 、糜蛋白酶（Ｃｈｙ） 的工作曲线。测定了人血清中的蛋白质总量，结果可靠。

铬Ⅵ-酸性铬蓝K-过氧化氢体系催化动力学光度法测定痕量铬Ⅵ

研究了在六次甲基四胺 -盐酸缓冲介质 ( pH 5 5 )中 ,痕量铬 催化过氧化氢氧化酸性铬蓝K的褪色反应 ,测得其反应表观活化能为 84 82kJ/mol,据此建立了一种测定痕量铬的新方法。在加入适量EDTA情况下 ,常见离子均不干扰铬的测定。方法检出限为 1× 10 - 3μg/mL ,在 2 5mL溶液中 ,线性范围为 0～ 12 μgCr 。该方法具有灵敏度高、选择性好、线性范围宽等特点 ,用于铁标样中铬的测定 。

血清蛋白质与氯磺酚K反应及其分析应用的研究

发现有机小分子氯磺酚K与生物活性物质蛋白质能发生染色反应 ,在pH4.30的缓冲溶液中 ,红色的氯磺酚K与无色的牛血清白蛋白形成蓝紫色复合物 ,其最大吸收波长为624nm ,较试剂本身红移约74nm ,表观摩尔吸光系数达2.49×105L·mol -1·cm -1,线性范围为0～240μg/mL。实验制定的几种蛋白质的工作曲线 ,其灵敏度和线性范围与牛血清白蛋白基本一致 ,用于临床中人血清蛋白质的测定 ,结果令人满意。

K^+对盐胁迫下罗布麻生长及离子吸收分配的效应

通过温室盆栽试验,研究了低钾(0.01mmol·L-1)和正常钾(2.5mmol·L-1)水平对NaCl胁迫下罗布麻(Apocynum venetum)生长和离子吸收分配的影响。结果表明,随着介质中NaCl浓度的增加,罗布麻的根、茎、叶的生物量和株高呈下降趋势;但相同浓度NaCl处理下,低钾和正常钾之间无显著差异(P>0.05)。罗布麻各器官中Na+含量随介质NaCl浓度的增加显著上升(P<0.05),叶中上升幅度明显大于根和茎;叶和茎中K+随介质NaCl浓度的增加显著下降,但仍维持较高水平,根中K+浓度能保持稳定;低钾和正常钾水平下,与无盐胁迫(对照)相比,50mmol·L-1 NaCl处理植株叶中K+浓度无显著变化。在对照条件下,罗布麻体内积累大量K+,其叶中K+浓度是Na+的15倍多。可见,增强K+的选择性吸收和运输,保持叶部较高的K+含量和K+/Na+比是罗布麻适应盐逆境的重要生理机制。

多波长K系数法测定混合干扰组分

本文提出测定混合干扰组分的多波长K系数法,给出了算式△A=A-sum from n=1 to n(K_iA_i)=kC。测定采用一个测量波长及与干扰组分个数相等的参数比波长。以本法对PAR-Co、Ni、Cu、Zn体系进行了测定,获较满意的结果。

牛血清白蛋白与酸性铬兰K结合反应的研究

本文对在酸性溶液中牛血清白蛋白与酸性铬兰K结合反应进行了研究。在pH 2 87盐酸 乙酸钠缓冲体系中 ,随着BSA浓度的逐渐增大 ,酸性铬兰K在 5 2 3nm的吸光度下降 ,吸收峰向长波方向移动。研究表明牛血清白蛋白与酸性铬兰K在通过静电引力而结合 ,结合反应符合相分配模型 ,并探讨了酸度、试剂浓度、离子强度对结合反应以及表观结合常数Kc、结合数n ,Sandell灵敏指数的影响 ,对反应时间、表面活性剂对体系的影响以及工作曲线进行了研究。

吸光度比值K系数法测定安痛定注射液的含量

吸光度比值Ｋ系数法是一种可以同时测定多元混合组分的新的分光光度法。本文成功地应用该法测定了安痛定注射液中氨基比林、安替比林和巴比妥三种组分的含量。其平均回收率和相对标准偏差分别为９８．９６％，０．４１％；１００．６％，０．３４％；９８．３３％，０．６５％。本法简便快速，结果准确可靠。