Near infrared fluorescent dye and its synthesis process

Near infrared fluorescent probe for detecting zinc ion in cell and its synthesis method and use

Easy-to-cut water atomized steel powder and production method thereof

The invention provides free-cutting water atomized steel powder and a production method thereof. The free-cutting water atomized steel powder comprises the following specific chemical compositions: more than 0.30 to 0.40 percent of S, and 0.10 to 0.30 percent of Mn. The method for producing the free-cutting water atomized steel powder comprises the following steps: a process of smelting in an electric arc furnace, a process of refining in a refining furnace, a process of atomizing by water and a process of secondary reducing, wherein in the process of the refining, the content of S of molten steel is improved and stabilized over 0.30 percent by the mode of adding high sulfurous iron alloy in the molten steel, thereby ensuring the content of S in steel powder is controlled at more than 0.30 percent but not exceeds the range of 0.40 percent. Free-cutting elements added in the process of the refining ensures evenness and stability of compositions of the molten steel, particularly an operation ...

Determination method of high voltage direct current converter commutation overlap angle

The invention discloses a determination method of a high voltage direct current converter commutation overlap angle, aiming to solve the problem that a traditional method for calculating a commutation overlap angle can not take nonideal factors including background harmonics into consider to cause poor design performance of a wave filter. The method comprises the following steps of dividing the working period of a converter into six commutation sections and six non-commutation sections; establishing a differential equation to each commutation section by considering factors such as background harmonic interference, asymmetric fundamental voltage, asymmetric converter trigger angle distances, commutation impedance deviation and the like; and accurately calculating the commutation overlap angle. The invention efficiently enhances the calculation efficiency when ensuring the accuracy and can enhance the design quality of an alternating current converter.

Manufacturing method of alloy steel powder by spraying

A process for preparing water-atomized alloy steel powder features that the original step such as smelting, water atomizing, dewatering, drying and high-temp. reducing are all such improved that the time and sequence for adding alloy elements in the smelting step are optimized, and the protection of inertial gas is used in the other steps for controlling the oxygen content of product to less than0.15%. Its advantages are high quality of product and low cost.

Design method for power transmission system line model

The invention relates to a design method for a power transmission system line model, which comprises the following aspects that: (1) the series expansion mode of the conventional design method is changed, and a hyperbolic sine function sh and hyperbolic cosine function ch series expansion mode adopted by the conventional algorithm is changed into a hyperbolic cotangent function cth and hyperbolic cosecant function csch series expansion mode, so that the problem that high-frequency series and terms are increased is solved, and calculation is simplified on the premise of ensuring accuracy; and (2) the problem that the terms of the series may be not converged in the hyperbolic cotangent function cth and hyperbolic cosecant function csch series expansion mode is solved, a line is subjected to segment processing, and the convergence of the series under the long-line condition is ensured. The invention provides the design method for the power transmission system line model which has high accuracy ...

Designing method of equivalent triple-tuned filter based on single-tuned filter

The invention relates to a designing method of an equivalent triple-tuned filter based on single-tuned filter. The triple-tuned filter is equivalent to three single-tuned filters so as to obtain corresponding parameters of the triple-tuned filter; the designing method specifically comprises the following steps of: (1) according to harmonic characteristic of the system respectively defining the reactive powers to be output by three equivalent single-tuned filters as Q1, Q2 and Q3, and respectively defining harmonic wave times to be inhibited as N1, N2 and N3; (2) computing capacitance inductance parameters of three single-tuned filters; (3) enabling three single-tuned filters to be equivalent to a triple-tuned filter, and obtaining the parameters of the triple-tuned filter through the equivalent formula. A method and an accuracy formula for computing the parameter of the single-tuned filter are provided by the invention; in the process of computing the parameter of the triple-tuned filter ...

Determination method of high voltage direct current converter commutation overlap angle

The invention discloses a determination method of a high voltage direct current converter commutation overlap angle, aiming to solve the problem that a traditional method for calculating a commutation overlap angle can not take nonideal factors including background harmonics into consider to cause poor design performance of a wave filter. The method comprises the following steps of dividing the working period of a converter into six commutation sections and six non-commutation sections; establishing a differential equation to each commutation section by considering factors such as background harmonic interference, asymmetric fundamental voltage, asymmetric converter trigger angle distances, commutation impedance deviation and the like; and accurately calculating the commutation overlap angle. The invention efficiently enhances the calculation efficiency when ensuring the accuracy and can enhance the design quality of an alternating current converter.

Pyrrole dimethine fluorescent dyes as well as synthetic method and use thereof

The invention provides a pyrrole di-methine fluorescent dye and a synthesis method and application; the synthesis method is as follows: a. preparing 2-phenylaziridine from styrene; b. adding 2-phenylaziridine into acetophenone, and reacting to produce 2, 4-diphenylpyrrole in the presence of sodium hydride under room temperature; c. adding 2, 4-diphenylpyrrole into p-hydroxybenzaldehyde, then adding chloranil according to the weight proportion 2, 4-diphenylpyrrole : chloranil =1:3-7; reacting under room temperature with stirring, removing excessive chloranil after reaction, and spinning dry to get blue solid pyrromethene; d. adding blue solid pyrromethene into dichloromethane for dissolution, then adding boron trifluoride diethyl etherate under the protection of inert gas, and reacting under room temperature; after reaction, adding chloroform and extracting 2 to 3 times; combining extract liquids, water washing, drying by anhydrous magnesium sulfate, spinning dry, and column separation to ...

Manufacturing method of alloy steel powder by spraying etc.

A process for preparing water-atomized alloy steel powder features that the original step such as smelting, water atomizing, dewatering, drying and high-temp. reducing are all such improved that the time and sequence for adding alloy elements in the smelting step are optimized, and the protection of inertial gas is used in the other steps for controlling the oxygen content of product to less than0.15%. Its advantages are high quality of product and low cost.