A novel liquid chromatographic method with fluorescence detection for quantitation of tadalafil and dapoxetine hydrochloride in pharmaceutical dosage form and human plasma北大核心CSCD

Tadalafil( TAD)and dapoxetine HCl( DAP)are recently co-formulated and both show native fluo-rescence. Therefore,a novel,accurate,specific and sensitive reversed-phase high performance liquid chroma-tographic method with fluorescence detection was developed and validated for their separation and quantitation in dosage form and human plasma using avanafil as an internal standard( IS). Separation was achieved using isocratic elution within 7. 0 min on C18 column and acetonitrile-0. 15% triethylamine( 40∶60,v/v;pH 4)as a mobile phase. The flow rate was 1. 0 mL/min and the detection was time-programmed at 330,410 and 370 nm for TAD,DAP and IS,respectively,after excitation at 236 nm. The linear ranges from 0. 01 to 30. 00 μg/mL for each drug with the limits of detection of 4. 20 and 7. 20 ng/mL for TAD and DAP,respectively. The method was validated in accordance to the International Conference on Harmonization( ICH)guidelines and was successful-ly applied to spiked human plasma with mean recoveries of 98. 17% and 98. 83% for TAD and DAP respectively.     

Effect of Second Order Chemical Reaction on MHD Free Convective Radiating Flow over an Impulsively Started Vertical Plate

An attempt has been made to study laminar convective heat and mass transfer flow of an incompressible, viscous and electrically conducting fluid over an impulsively started vertical plate with conduction-radiation embedded in a porous medium in presence of transverse magnetic field. The influence of both second order chemical reaction and heat generation are taken into account. The governing coupled partial differential equations are solved by Crank-Nicolson method. The effects of important physical parameters on the velocity, temperature and concentration have been analyzed through graphs. The results of the present study agree well with the previous solutions. Applications of the present study are shown in material processing systems and different industries. The important findings of present study are: chemical reaction parameter acts as resistive force to reduce the velocity whereas heat source parameter enhances the velocity.     

辐射增强PP／BR共混体系的力学性能

研究了在多官能团单体－三烯丙基异氰酸酯存在下，共混体系聚丙烯／１．４－聚丁二烯橡胶的辐射效应，用ＤＳＣ，动态粘弹谱对其进行表征。结果显示，三烯丙基异氰酸酯主要分布于聚丙烯／１．４－聚丁二烯橡胶共混物的界面自高能射线作用下，被引发参与界面反应，从而改善了共混体系的相容性，增强也界面粘接，提高了共混物的力学性能。     

激光驻波场作用下原子束横向速度聚束

分别从理论和实验上研究了在负失谐强激光驻波场作用下，原子速度聚集在某一特定速度附近的现象，即速度聚束，产生速度聚束的原因是，当原子的速度小于某一临界速度时，激光对原子的辐射压力加热原子，而当原子速度大于这个临界速度时则冷却原子，因此原子将伙集于这个临界速度附近。     

An assessment of the high frequency boundary element and Rayleigh integral approximations

This paper revisits the popular Rayleigh integral approximation and also considers a second approximation, the high frequency boundary element method, which is similar to the Rayleigh integral. The Rayleigh integral approximation under consideration is enhanced so that only the elements visible to a particular point in the field are used to calculate the sound pressure at that point. It is demonstrated how both the Rayleigh integral and high frequency boundary element method are approximations to the boundary integral equation so that similarities between the two methods are recognized. Several test cases were conducted in order to assess and compare both methods. The first set of test cases was the pulsating and oscillating sphere. Both methods were then compared on more applied examples including a running engine, construction cab, and transmission housing. It was concluded that though both methods can reliably predict the sound power for some problems, the high frequency boundary element method is the more robust.     

固体高分辨~(13)C NMR研究γ线辐照对结晶聚乙稀聚集态结构的影响

结晶聚乙烯(PE)经~(60)Coγ线辐照后,用固体高分辨~(13)C NMR CP/DD/MAS方法观测解析了辐射效果与具有片晶结构的结晶相,结晶—橡胶状无定形界面相以及橡胶状无定形相的聚集态结构的关系。考察了各相中的~(13)C核自旋—晶格弛豫和自旋-自旋弛豫行为及辐照对其影响。得到辐照后产生交联,破坏,相转变及晶型变化等有意义的结果,对PE的辐照效应和机制的探讨提供了核磁共振的新实验证据。     

The study of diffraction radiation oscillation

Theoretical and experimental study of Diffraction Radiation Oscillator (DRO) is reported in this paper, it is the first work done in P. R. China. The sphere-cylindrical open cavity used in the DRO has been analysed, the method for testing the field profile and the cold measurement of the open cavity have been worked out. The experimental device was manufactured in our lab. and the theoretical analysis and experimental study of the device have been carried out. The main experimental results are: from 2000 V to 4000 V, the tube operates in the 60–87 GHz band, and the maximum output power is about 800 mW.     

Radiation preparation of nano-powdered styrene-butadiene rubber (SBR) and its toughening effect for polystyrene and high-impact polystyrene

Nano-powdered styrene-butadiene rubber (NPSBR) was synthesized based on the styrene-butadiene rubber (SBR) latex via gamma radiation crosslinking followed by spray drying. Two functional monomers, 2-ethyl hexyl acrylate (2-EHA) and trimethylolpropane triacrylate (TMPTA) were used as crosslinking agents. It was found that both 2-EHA and TMPTA can improve the radiation crosslinking of SBR latex. Transmission electron microscope (TEM) and scanning electron microscope (SEM) revealed that the NPSBR has a particle size similar to that of SBR latex with a diameter of 100 nm due to the high degree of crosslinking of SBR. Mechanical testing results showed that NPSBR could toughen polystyrene (PS) and high-impact polystyrene (HIPS) effectively. In addition, NPSBR is more suitable to toughen HIPS than PS at low rubber content.     

Radiation induced effects on particulate composites from epoxy resin and fly-ash

In this paper gamma-radiation damages and effects on an epoxide matrix and on its particulate composite with coal fly ash have been studied; the curing of both formulations was carried out at room temperature by means of tetraethylenepentamine and of a tailored polyalkylenepolyaminophenolic product. The change on mechanical properties following the irradiation in air at room temperature has been tested as a function of the total absorbed dose. The chemical modification induced by the ionizing radiation on the matrices have been investigated by means of infrared spectrophotometry and differential scanning calorimetry. The high radiation resistance of the matrix and above all of the particulate composite suggests its use for the confinment of low and medium activity radwastes (nuclear or medical).     

Studies on calcium alginate stanch fibre by radiation sterilization and its biology

This paper explored the technical feasibility of surgical calcium alginate stanch fibre steriliged by radiation. By detecting the biological load before and after irridiation the optimum sterilized dose is 10–12KGY. By determing the Ca⁺⁺ content, a linear regression equation relative to adsorbed dose and Ca⁺⁺ content percentage is given out. lgD=0.13449+7.966x10^-3N(r=0.9935) The result of biological studies of radio sterilized stanch fibre to be applied on adult rabbits and NIH mice by biologic test was performed that the γ-ray sterilized stanchfibre had no irritant effect on both the health and the wound skin, crust formation rate was better than of the check. The total and partial irritation intensity and the allergization rate became zero.