Towards improved design of boring bars part 1: Dynamic cutting force model with continuous system analysis for the boring bar performance

The vibrational amplitude is generally large in the case of a boring bar due to its slenderness. A dynamic cutting force model has been presented to take this large amplitude into account. The boring bar is then modelled as a cantilever with this dynamic force acting at the free end and a generalized continuous system model is obtained. This model is solved for the specific case of boring with a zero side cutting edge angle for which published results are available. A reasonably close agreement is found between the proposed model and the experimental results.     

IMPROVEMENTS IN GAS INDUCING IMPELLER DESIGN

Rate of gas induction, static pressure, mixing time and power consumption have been measured in 0.57 m i.d. vessel. Different types of impellers namely shrouded disc turbine, shrouded curved blade turbine and pitched blade turbine were used. The impeller diameter was varied from 0.15-0.25 m and the impeller speed was varied from 3 to 20 r/s.

The pitched blade turbine was found to give 30-60 per cent higher rates of gas induction as compared with the best design reported in the literature. The mixing time was found to be lower by a similar magnitude. Moreover in the case of pitched blade turbine it was found that the gas was getting induced radially as well as axially. This eliminates the necessity of the diffuser and hence reducing the complexities in the mechanical structure.     

光催化剂SrTiO3的制备及其性能的研究

论述用化学液相共沉淀法制备SrTiO_3的最佳条件,及在不同的活化条件下对SrTiO_3光催化性能的影响。此外还研究了掺入过渡金属氧化物对SrTiO_3催化性能的改善。     

应用免疫斑点法检测不同工艺灭活的乙肝血源疫苗中的前S_1和S_2蛋白

作者应用前 S_1、前 S_2和 HBsAg/a 单克隆抗体,用免疫斑点法(Immuno-spot)检测同一批的乙肝表面抗原分别经加热灭活和三步化学灭活后的前 S_1和前 S_2蛋白保留情况,比较了两种工艺对前 S_1和前 S_2蛋白的影响。结果表明;加热灭活可保留前 S_1和前 S_2蛋白,三步化学灭活使前 S_1和前 S_2蛋白丢失,从抗原组成上看,加热灭活后的抗原更接近自然抗原。首次报告了含有前 S_1蛋白的乙肝疫苗,并对前 S_1和前 S_2蛋白在乙肝血源疫苗中的可能作用进行了讨论。     

微波谐振腔模式数的程序求解法

微波谐振腔在无线通信领域应用广泛。在简要微波谐振腔的基础上,给出了用程序求解谐振模式数的方法,并利用C++实现了对给定尺寸矩形谐振腔模式数的求解。     

Humidity sensor composed of a microporous film of polyethylene-graft-poly-(2-acrylamido-2-methylpropane sulfonate)

Summary Inside a microporous polyethylene film, 2-acrylamido-2-methylpropane sulfonic acid was graft polymerized by ultraviolet irradiation. A humidity sensor was fabricated by depositing gold electrodes on both sides of the grafted film. The impedance was measured as a function of humidity for the acid and alkali salts of sulfonate. The sensor has long term stability and is resistant to water.     

Saponification kinetic study of mica-acrylonitrile graft copolymers

Kinetics of alkaline hydrolysis of mica-acrylonitrile graft copolymers was studied. The dependence of alkali concentration and the time of hydrolysis on the degree of saponification was determined. Chemical and spectroscopical techniques were used to determine the mechanism of hydrolysis.     

Seeded Crystallization of Leucite

The leucite crystallization kinetics from a hydrothermally derived precursor seeded with nano-crystalline leucite was investigated by X-ray diffraction and non-isothermal differential thermal analysis. The nano-crystalline leucite was prepared by high-energy milling of high-purity leucite powder and the leucite precursor was prepared by the hydrothermal method of silica sol, aluminum nitrate, and potassium nitrate. After the seeds were introduced, the crystallization temperature of the precursor was lowered by 100°C and the transition phase kalsilite did not appear during the crystallization process. When the seeded precursor was heat treated at 700°C, a small amount of cubic leucite was stabilized to room temperature. The seeded precursor showed an exothermic peak between 800° and 920°C under different heating rates. The activation energy for the growth of leucite from the seeded precursor was 256(SD9) kJ/mol.