A new sensitive adsorptive voltammetric method was described for the determination of zirconium at a carbon paste electrode (CPE) in the presence of alizarin complexone (ALC). Optimal analytical conditions are: 1.0?0...A new sensitive adsorptive voltammetric method was described for the determination of zirconium at a carbon paste electrode (CPE) in the presence of alizarin complexone (ALC). Optimal analytical conditions are: 1.0?0-6 or 5.0?0-7 mol/L ALC, 0. 20 mol/L HAC-NaAc (pH 4.3), accumulation for 60 s at 0 V (vs. SCE), and linear scanning from 0 V to 1.0 V at 250 mV/s. The peak potential of the complex is at 0.81 V. By using a model JP-303 polarographic analyzer, 2.0?0-10 mol/L (S/N=3) zirconium can be detected with a 90 s accumulation, when the 2nd-order derivative linear sweep technique is used, and the linear range is 6.0?0-10-2.0?0-8 mol/L (5.0?0-7 mol/L ALC) and 2.0?0-8-2.0?0-7 mol/L (1.0?0-6 mol/L ALC), respectively. The developed method was applied to the determination of trace zirconium in the ore samples with satisfactory results.展开更多
We can make mistakes at any age.Somemistakes we make are about money.But mostmistakes are about people.“When I got thatjob,did Jim really feel good about it as afriend?Or is he envious(嫉妒)of my luck?”“And Paul—W...We can make mistakes at any age.Somemistakes we make are about money.But mostmistakes are about people.“When I got thatjob,did Jim really feel good about it as afriend?Or is he envious(嫉妒)of my luck?”“And Paul—Why didn't I find that he wasfriendly just because I had a car?”When welook back,thinking about these,that can makeus feel bad.But when we look back.it's too late.展开更多
From the point of view of approximate symmetry, the modified Korteweg-de Vries-Burgers （mKdV-Burgers） equation with weak dissipation is investigated. The symmetry of a system of the corresponding partial differentia...From the point of view of approximate symmetry, the modified Korteweg-de Vries-Burgers （mKdV-Burgers） equation with weak dissipation is investigated. The symmetry of a system of the corresponding partial differential equations which approximate the perturbed mKdV-Burgers equation is constructed and the corresponding general approximate symmetry reduction is derived; thereby infinite series solutions and general formulae can be obtained. The obtained result shows that the zero-order similarity solution to the mKdV-Burgers equation satisfies the Painleve II equation. Also, at the level of travelling wave reduction, the general solution formulae are given for any travelling wave solution of an unperturbed mKdV equation. As an illustrative example, when the zero-order tanh profile solution is chosen as an initial approximate solution, physically approximate similarity solutions are obtained recursively under the appropriate choice of parameters occurring during computation.展开更多
A novel complex tri（o-bromobenzyl）tin ferrocenecarboxylate has been synthesized and its crystal structure was determined by X-ray diffraction. It belongs to orthorhombic, space group Pbca with a = 1.1340（3）, b = 1...A novel complex tri（o-bromobenzyl）tin ferrocenecarboxylate has been synthesized and its crystal structure was determined by X-ray diffraction. It belongs to orthorhombic, space group Pbca with a = 1.1340（3）, b = 1.7823 （4）, c = 3.0119（8） nm, V = 6.088（3） nm^3, Mr = 857.81,Z = 8, Dc = 1.872 g/cm^3,μ（MoKα） = 52.63 cm^-1, F（000） = 3328, R = 0.0683 and wR = 0.1057. The tin atom adopts a distorted tetrahedral coordination geometry. Further studies on the title complex have been performed with quantum chemistry calculation at the Lanl2dz basis set level using G98W package. The stability of the complex, some frontier molecular orbital energies and composition characteristics of some frontier molecular orbitals have been investigated.展开更多
Tricalcium phosphate Anhydrous Powder typically contains less than 10 ppm (mg/Kg) (w/w) manganese. This level can be determined utilizing Flame Atomic Absorption Spectrometer (AAS) and standard based on known standard...Tricalcium phosphate Anhydrous Powder typically contains less than 10 ppm (mg/Kg) (w/w) manganese. This level can be determined utilizing Flame Atomic Absorption Spectrometer (AAS) and standard based on known standards. A number of analytical methods are presently used for the analysis of metals in the biochemical. The instrumental techniques available are Inductively Coupled Plasma (ICP/MS), X-Ray Fluorescence, UV-VIS Spectrophotometry, and Atomic Absorption Spectrometry. Flame AA has gained widespread acceptance as an analytical technique and is used for many applications. In this study, we have determined the amount of manganese metal present in Tricalcium Phosphate (TCP) using Flame Atomic Absorption Spectrophotometer. The method has high precision and accuracy. The percent recovery was found to be 99.8% for spiked sample. The results meet the requirement.展开更多
A multi-try counter-meshing gears stronglink based on micro electromechanical system （MEMS） technology is introduced, including research, design, couple and fabrication of unique signal （UQS） for some specified fi...A multi-try counter-meshing gears stronglink based on micro electromechanical system （MEMS） technology is introduced, including research, design, couple and fabrication of unique signal （UQS） for some specified fields of information security. The stronglink consists of two groups of metal counter-meshing gears, two pawl/ratchet mechanisms, two driving micromotors and two resetting micromotors. The resetting micromotors make counter-meshing gears withdraw by raising pawls so that the interfered counter-meshing gears will be relieved. The energy-coupling element is a photoelectric sensor with a circular notched plate. The counter-meshing mechanism is fabricated using the ultraviolet-lithographie~ galvanoformung and abformung （UV-LiGA） process and a precision mechanical technique. The stronglink can be tried several times if the correct resetting code is known.展开更多
文摘A new sensitive adsorptive voltammetric method was described for the determination of zirconium at a carbon paste electrode (CPE) in the presence of alizarin complexone (ALC). Optimal analytical conditions are: 1.0?0-6 or 5.0?0-7 mol/L ALC, 0. 20 mol/L HAC-NaAc (pH 4.3), accumulation for 60 s at 0 V (vs. SCE), and linear scanning from 0 V to 1.0 V at 250 mV/s. The peak potential of the complex is at 0.81 V. By using a model JP-303 polarographic analyzer, 2.0?0-10 mol/L (S/N=3) zirconium can be detected with a 90 s accumulation, when the 2nd-order derivative linear sweep technique is used, and the linear range is 6.0?0-10-2.0?0-8 mol/L (5.0?0-7 mol/L ALC) and 2.0?0-8-2.0?0-7 mol/L (1.0?0-6 mol/L ALC), respectively. The developed method was applied to the determination of trace zirconium in the ore samples with satisfactory results.
文摘We can make mistakes at any age.Somemistakes we make are about money.But mostmistakes are about people.“When I got thatjob,did Jim really feel good about it as afriend?Or is he envious(嫉妒)of my luck?”“And Paul—Why didn't I find that he wasfriendly just because I had a car?”When welook back,thinking about these,that can makeus feel bad.But when we look back.it's too late.
基金supported by the National Natural Science Foundations of China(Grant Nos 10735030,10475055,and 90503006)the National Basic Research Program of China(Grant No 2007CB814800)+1 种基金the Science Foundation for Post Doctorate Research from the Ministry of Science and Technology of China(Grant No 20070410727)the Natural Science Basic Research Plan in Shaanxi Province,China(Grant No SJ08A09)
文摘From the point of view of approximate symmetry, the modified Korteweg-de Vries-Burgers （mKdV-Burgers） equation with weak dissipation is investigated. The symmetry of a system of the corresponding partial differential equations which approximate the perturbed mKdV-Burgers equation is constructed and the corresponding general approximate symmetry reduction is derived; thereby infinite series solutions and general formulae can be obtained. The obtained result shows that the zero-order similarity solution to the mKdV-Burgers equation satisfies the Painleve II equation. Also, at the level of travelling wave reduction, the general solution formulae are given for any travelling wave solution of an unperturbed mKdV equation. As an illustrative example, when the zero-order tanh profile solution is chosen as an initial approximate solution, physically approximate similarity solutions are obtained recursively under the appropriate choice of parameters occurring during computation.
基金Supported by the Key Foundation of Education Committee of Hunan Province (06A009)the Natural Science Foundation of Hunan Province (05JJ40015, 06JJ50022)
文摘A novel complex tri（o-bromobenzyl）tin ferrocenecarboxylate has been synthesized and its crystal structure was determined by X-ray diffraction. It belongs to orthorhombic, space group Pbca with a = 1.1340（3）, b = 1.7823 （4）, c = 3.0119（8） nm, V = 6.088（3） nm^3, Mr = 857.81,Z = 8, Dc = 1.872 g/cm^3,μ（MoKα） = 52.63 cm^-1, F（000） = 3328, R = 0.0683 and wR = 0.1057. The tin atom adopts a distorted tetrahedral coordination geometry. Further studies on the title complex have been performed with quantum chemistry calculation at the Lanl2dz basis set level using G98W package. The stability of the complex, some frontier molecular orbital energies and composition characteristics of some frontier molecular orbitals have been investigated.
文摘Tricalcium phosphate Anhydrous Powder typically contains less than 10 ppm (mg/Kg) (w/w) manganese. This level can be determined utilizing Flame Atomic Absorption Spectrometer (AAS) and standard based on known standards. A number of analytical methods are presently used for the analysis of metals in the biochemical. The instrumental techniques available are Inductively Coupled Plasma (ICP/MS), X-Ray Fluorescence, UV-VIS Spectrophotometry, and Atomic Absorption Spectrometry. Flame AA has gained widespread acceptance as an analytical technique and is used for many applications. In this study, we have determined the amount of manganese metal present in Tricalcium Phosphate (TCP) using Flame Atomic Absorption Spectrophotometer. The method has high precision and accuracy. The percent recovery was found to be 99.8% for spiked sample. The results meet the requirement.
基金the High-Technology Research and Development Program of China (Grant No.863-2003AA404210,the second phase 863-2005AA404250,863-2003AA404210 and the third phase 863-2006AA01Z443)
文摘A multi-try counter-meshing gears stronglink based on micro electromechanical system （MEMS） technology is introduced, including research, design, couple and fabrication of unique signal （UQS） for some specified fields of information security. The stronglink consists of two groups of metal counter-meshing gears, two pawl/ratchet mechanisms, two driving micromotors and two resetting micromotors. The resetting micromotors make counter-meshing gears withdraw by raising pawls so that the interfered counter-meshing gears will be relieved. The energy-coupling element is a photoelectric sensor with a circular notched plate. The counter-meshing mechanism is fabricated using the ultraviolet-lithographie~ galvanoformung and abformung （UV-LiGA） process and a precision mechanical technique. The stronglink can be tried several times if the correct resetting code is known.
