基于混合发展的超声速段射流式COIL的数值优化

应用CFD技术,发展三维多组分化学反应流计算程序,对采用超声速段射流方式的氧碘化学激光进行数值模拟,考察分解率与增益等参考变量的详细三维分布.计算结果说明,超声速区域的高速流动以及混合效率降低使COIL无法在有限空间内完成整个运转流程;提高碘含量以加快反应速度的手段导致主流无法提供足够的载能介质,无法形成合理增益.在不改变喷管长度的前提下,提出主流无载气方式的探索,结果证明了超声速段射流方式采用无载气主流配置的可行性与优势,通过减小气流速度保证混合与化学反应在光腔上游完成,在合理的流量配比下光腔位置处可得到1.3%cm-1的增益峰值

Investigations of phase inversion and frictional pressure gradients in upward and downward oil–water flow in vertical pipes

The present study has attempted to investigate phase inversion and frictional pressure gradients during simultaneous vertical flow of oil and water two-phase through upward and downward pipes. The liquids selected were white oil (44 mPa s viscosity and 860 kg/m3 density) and water. The measurements were made for phase velocities varying from 0 to 1.24 m/s for water and from 0 to 1.87 m/s for oil, respectively. Experiments were carried either by keeping the mixture velocity constant and increasing the dispersed phase fraction or by keeping the continuous phase superficial velocity constant and increasing the dispersed phase superficial velocity. From the experimental results, it is shown that the frictional pressure gradient reaches to its lower value at the phase inversion point in this work. The points of phase inversion are always close to an input oil fraction of 0.8 for upward flow and of 0.75 for downward flow, respectively. A few models published in the literature are used to predict the phase inversion point and to compare the results with available experimental data. Suitable methods are suggested to predict the critical oil holdup at phase inversion based on the different viscosity ratio ranges. Furthermore, the frictional pressure gradient is analyzed with several suitable theoretical models according to the existing flow patterns. The analysis reveals that both the theoretical curves and the experimental data exhibit the same trend and the overall agreement of predicted values with experimental data is good, especially for a high oil fraction.

Effect of Nozzle Temperature on the Performance of a 1 kW H2-N2 Arcjet Thruster

A 1 kW-class arcjet thruster was ¯red in a vacuum chamber at a pressure of 18 Pa. A gas mixture of H2 : N2 = 2.8 : 1.5 in volume at a total °ow rate of 4.3 slm was used as the propellant with an input power ¯xed at 860 W. The time-dependent thrust, nozzle temperature and inlet pressure of the propellant were measured simultaneously. Results showed that with the increase in nozzle temperature the thrust decreased and various losses increased. The physical mechanisms involved in these effects are discussed.

铜川市工业三废污染问题及治理研究

IEECAS SKLLQG

Compound specific D/H ratios and molecular distributions of higher plant leaf waxes as novel pale oenvironmental indicators in the Chinese Loess Plateau

IEECAS SKLLQG

仓鼠V79细胞对加速碳离子的辐照致死效应

分别测定了传能线密度（LET）为125．5、200、700keV／μm碳离子辐照仓鼠V79细胞的存活曲线，由存活曲线确定了上述3种碳离子辐照时V79细胞的失活截面依次为7．86±0．17、10．44±1．11、32．32±3．58μm2。以V79细胞对60Coγ射线的存活响应为参考值，给出了对应于上述3种碳离子照射周％、20％、50％、80％存活水平下的相对生物学效应（RBE），结果表明125．5keV／μm碳离子的RBE值在各个存活水平下都为最大。提示：以存活为生物学终点的RBE最大值在LET值小于200keV／μm的碳离子辐照时出现。

High-efficiency transfer and expression of AdCMV-p53 in human hepatocellular carcinoma cells induced by low-dose carbon-ion radiation

Objective To investigate whether the irradiation with C-beam could enhance adenovirus-mediated transfer and expression of p53 in human hepatocellular carcinoma. Materials and methods HepG2 cells were exposed to C-beam or gamma-ray and then infected with replicationdeficient adenovirus recombinant vectors containing human wild-type p53 or green fluorescent protein, respectively. The transfer efficiency and expression level of the exogenous gene were detected by flow cytometric analysis. Cell survival fraction was detected by clonogenic assay. Results The transfer frequency in C-beam or gamma-irradiated groups increased by 50-83% and 5.7-38.0% compared with the control, respectively (P < 0.05). Compared with C-beam alone, p53 alone, and gamma-ray with p53, the percentages of p53 positive cells for 1 Gy C-beam with p53 increased by 56.0-72.0%, 63.5-82.0%, and 31.3-72.5% on first and third day after the treatments, respectively (P < 0.05). The survival fractions for the 2Gy C-bearn and AdCMV-p53 infection groups decreased to similar to 2%. Conclusion C-beam irradiation could significantly promote AdCMV-green fluorescent protein transfer and expression of p53.

水肥交互作用对黄土高原南瓜光合特性及其产量的影响

通过不同的灌水和施肥处理,研究水肥交互作用对南瓜光合特性日变化及产量的影响,结果表明:水分与施肥因子对南瓜叶片的光合特性和产量有重要影响,在水分胁迫的情况下,肥水交互作用不显著,在水分较低的情况下,二者表现互为限制条件的协同作用;在水分较高的情况下,肥水交互作用转变成顺序加和作用。其中单因素效应大小表现为:氮>水>磷,耦合效应大小表现为:氮与水耦合>氮与磷耦合>磷与水耦合。在水分适宜时,适宜的施肥量(施氮量50kg/hm2、施磷量35 kg/hm2)可以提高南瓜光合速率和产量,不施肥或施肥量过高都会影响南瓜光合速率和产量。

细胞色素c在羟基磷灰石修饰玻碳电极上的直接电化学

采用沉淀法合成羟基磷灰石纳米晶体 ,由于具有独特的多吸附位点特征 ,羟基磷灰石可作为一种新型电子传递促进剂用于细胞色素c的直接电化学研究 .在pH 7.0的磷酸盐缓冲溶液中 ,细胞色素c在羟基磷灰石修饰玻碳电极表面于0 0 74V (vs .Ag/AgCl)处有一对准可逆的氧化还原峰 ,为细胞色素c血红素辅基Fe(Ⅲ ) /Fe(Ⅱ )电对的特征峰 .实验结果表明细胞色素c与羟基磷灰石之间的静电作用 ,促进了细胞色素c在玻碳电极表面扩散控制的准可逆单电子转移过程 .讨论了电位扫描速度、溶液离子强度对细胞色素c直接电化学的影响

Voltammetric Behavior of ethambutol on a glassy carbon electrode and its application

The anodic voltammetric behavior of ethambutol in the presence of various electrolytes was studied by direct-current voltammetry, differential-pluse voltammetry and cyclic voltammetry at a glassy carbon electrode. In a medium of 0.039 mol/L Na2HPO4, an oxidative peak of ethambutol was obtained. The peak potential is at about 1.04 V( vs. Ag/AgCl). The height of the peak is linearly increased with the concentration of ethambutol over the range of 3 mg/Lsimilar to1000 mg/L. The method has been used for the direct determination of ethambutol in tablets. The average recovery of ethambutol in urine samples is 84.7%. Experimental results proved that the electrode reaction was diffusion controlled and irreversible.