测量行波管电子注的法拉第筒的热分析

利用ANSYS软件对测量行波管电子注截面的法拉第筒探头进行了热分析研究.分析了在单脉冲情况下,测量各种直径的不同脉冲功率密度的电子注、不同脉冲宽度对法拉第筒温度的影响,研究了测量不同功率密度的电子注可以使用的脉冲宽度.结果表明,仅法拉第筒上的注斑区域温度迅速上升,温度梯度较大,其它部分温度基本不变,为保证法拉第筒能够持...     

Silane modification and characterization of activated carbon

Activated carbons have been wildly used as adsorbents for various purpose. When used in a cigarette filter activated carbon can selectively remove a number of the vapor phase compounds to varying degrees of efficiency. To improve the wet-feeling of cigarette smoke with AC in the filter, a new method is developed to chemically functionalize a coal-based activated carbon (AC) based on silanization reaction. Silanization using 3-glycidoxypropyltrimethoxy silane was performed after the oxidized AC was reduced by lithium aluminum hydride.     

Effect of exogenous softwood on thermal decomposition of reconstituted tobacco sheet

In recent years, reconstituted tobacco sheet (RTS) has played an increasingly vital role in reducing tumorigenicity for tobacco industry. In this paper, two plant fibers of tobacco pulp (TP) and softwood pulp (SP) were added independently as strengthening agents during the paper-making process to manufacture RTS (TP-RTS and SP-RTS). The effects of exogenous SP on the CO yield in cigarette mainstream smoke, thermal behavior, and gaseous products evolution properties of RTS were evaluated and compared with TP. The CO yield in cigarette mainstream smoke was studied using smoking machine and CO analyzer. The thermal behavior of two RTS was studied by thermogravimetric (TG) analysis, and the gaseous products were investigated by Fourier transform infrared spectrometer (FTIR). CO yield in cigarette mainstream smoke results demonstrated that SP-RTS (3.16 mg per puff) presented higher CO yield per puff than TP-RTS (2.83 mg per puff). TG analysis results demonstrated that the maximum mass loss rate of SP-RTS (23.3 % min^?1) was drastically higher than that of TP-RTS (15.8 % min^?1). FTIR results illustrated that SP-RTS presented stronger absorbance intensity associated with generation of more gaseous products than TP-RTS. In the thermal decomposition stage, the maximum mass loss rate of SP (78.6 % min^?1) was clearly higher than that of TP (38.4 % min^?1), and SP increased the generation of gaseous products compared to TP.     

硅芯片多层薄膜折射率的测量

本文介绍一种测量透明薄膜折射率的“磨角—干涉”法。根据光干涉原理,推导了薄膜折射率的表达式n=1+△N1/△N2。此法可用于测量半导体器件和大规模集成电路芯片中的单层或多层膜的折射率。     

Effects of melamine phosphate on the thermal decomposition and combustion behavior of reconstituted tobacco sheet

In this paper, first the MP-modified reconstituted tobacco sheet (RTS) was prepared by a paper-making process. Thermogravimetric analysis coupled to Fourier transform infrared spectrometer (TG-FTIR) had been used to investigate the influences of melamine phosphate (MP) on the thermal decomposition and the formation of evolved volatile products of RTS. TG-FTIR results illustrated that the incorporation of MP into RTS could retard the thermal decomposition of the major components of RTS and meanwhile lead to the formation of more thermally stable char. Moreover, the main gases released during the pyrolysis of RTS and MP-modified RTS were H₂O, CO₂, CO, NH₃, carbonyl compounds, alcohols, phenols, alkanes, and alkenes. The presence of MP changed the formation of evolved volatile products of RTS obviously. The effects of MP on the combustion behavior of RTS were studied by micro-scale combustion calorimetry and cone calorimetry. Results demonstrated that the formation of combustible gases was mainly determined by the thermal decomposition stage occurred in the temperature range of 150–600 °C. The incorporation of MP into RTS influenced the release of fuel gases and the char formation in the process of the thermal decomposition of RTS, and eventually retarded the flammability and combustibility of RTS.     

金属掺杂钨基合金阴极的二次电子发射系数研究

实验中制备了W-Re,W-Sc,W-Zr,W-Y合金阴极,其中Re,Sc,Zr,Y元素所占合金阴极材料的质量分数都为5%。二次电子发射系数测试结果显示,Re掺杂合金阴极对提高纯钨阴极二次电子发射能力显著,掺杂5% Re的W-Re合金阴极材料具有最大二次电子发射系数,其值为1.8,相比于纯钨阴极,能够提高80%。鉴于Re对提高纯钨阴极二次电子发射能力显著,对Re掺杂质量分数分别为20%,10%,6%,5%,4%,3%W-Re合金阴极材料二次电子发射系数进行了研究,发现随着Re在W-Re合金阴极材料中含量的降低,其二次电子发射系数在不断增大,仅当Re含量下降至5%左右时,合金阴极具有最大二次电子发射系数,继续下降至4%,合金阴极二次电子发射系数不但没有升高,相反下降至1.41,当下降至3%时,合金阴极二次电子发射系数值迅速降低为1.1。     

Platelet aggregation inhibitors from Populus sieboldii Miquel.

The water extract of Populus sieboldii Miquel (Salicaceae) inhibited arachidonic acid-induced platelet aggregation. Pyrocatechol and salicyl alcohol were isolated as active constituents. Pyrocatechol showed an inhibitory effect on platelet aggregation induced by arachidonic acid with IC100 value of 4 microM, which was 25 times more potent than aspirin.     

Study on the inclusion behavior of p-sulphonatocalix[4]arene with 9-amino-acridine by spectrofluorometric titrations

Spectrofluorometric titrations have been performed to investigate the inclusion behavior of p-sulphonatocalix[4]arene (SC4A) and 9-amino-acridine (AA) in citrate buffer solution (pH 5.92). It was found that the fluorescence intensity of AA quenched regularly upon the addition of SC4A. The proposed interaction mechanism between SC4A and AA indicates that AA partially goes into the cavity of SC4A with the help of strong electrostatic interaction and hydrogen bonding, which formed by the protonated N atom and the amino groups of AA bonding with sulphonyl groups of SC4A, respectively. The inclusion ratio was 1:1 and the inclusion constant was 1.84 x 10(5) L mol(-1) at 25.0 degrees C.