短脉冲强X光泵浦产生光电离三体复合X光激光

介绍了激光打靶产生短脉冲强X光辐射的方法,给出了打钠靶的数值模拟结果。 数值研究短脉冲强钠X光泵浦氖激光介质的X光激光,通过在氖中加氢的办法降低了电子温 度,有效地提高了激光增益。研究了短脉冲强X光泵浦的高增益光电离三体复合X光激光机 制,提出了在大中型激光器上开展这种X光激光研究的想法。     

Modification of the Fractionated γ-Radiation-Induced Alteration in the Na+/K+-ATPase Activity of Radiosensitive Tissues by Vitamin A

The effect of pre or post-administration of vitamin A in ameliorating the radiation-induced alteration in intestinal and spleen Na⁺/K⁺-ATPase activity of rats was determined. Rats subjected to multifractionated γ-radiation (20 × 0.5 Gy) over the whole-body showed a significant reduction in Na⁺/K⁺-ATPase activity being more obvious in spleen than in intestine. Administration of vitamin A at a daily i. p. dose of 15,000 IU/kg bd. wt. for 7 days prior to fractionated γ-irradiation and thereafter twice weekly throughout the exposure period (as pretreatment regimen) or following the end of irradiation for 7 days (as posttreament regimen) afforded a significant protection from radiation-induced inhibition of spleen and intestinal Na⁺/K⁺-ATPase activity. Even though, pretreatment regimen is more efficient against radiation injury to this enzyme than posttreatment, so that its activity was nearly normalized in the first regimen. The regeneration of normal enzyme activity in the tissues of the vitamin A-pretreated group suggests that the intestinal and spleen epithelia in presence of vitamin A are rendered relatively radioresistant.     

Natural convection in a square cavity containing a nanofluid and an adiabatic square block at the center

The problem of free convection fluid flow and heat transfer of Cu–water nanofluid inside a square cavity having adiabatic square bodies at its center has been investigated numerically. The governing equations have been discretized using the finite volume method. The SIMPLER algorithm was employed to couple velocity and pressure fields. Using the developed code, a parametric study was conducted and the effects of pertinent parameters such as Rayleigh number, size of the adiabatic square body, and volume fraction of the Cu nanoparticles on the fluid flow and thermal fields and heat transfer inside the cavity were investigated. The obtained results show that for all Rayleigh numbers with the exception of Ra = 10⁴ the average Nusselt number increases with increase in the volume fraction of the nanoparticles. At Ra = 10⁴ the average Nusselt number is a decreasing function of the nanoparticles volume fraction. Moreover at low Rayleigh numbers (10³ and 10⁴) the rate of heat transfer decreases when the size of the adiabatic square body increases while at high Rayleigh numbers (10⁵ and 10⁶) it increases.     

Numerical investigations of supercavitation around blunt bodies of submarine shape

Cavitation occurs when liquid is subjected to rapid changes of pressure. If the local pressure is lower than the liquid saturation pressure, the liquid changes its phase into vapor. A fast moving solid body underwater will reduce the local pressure around the body. Under certain conditions, the local pressure can be lower than the water saturation pressure, accordingly causing cavitation. If the velocity of the moving body increases further, a supercavitation will occur. In this paper, the cavitation and supercavitation were studied by the SST k–ω turbulence model combined with a finite-rate mass transfer modeling under the mixture assumption. The validations of these models were performed through comparisons between numerical simulations and experiments. After the validations, the supercavitation generated by a high speed moving body, which can be described as a large bubble, was studied. The studies were on several blunt bodies, such as a submarine hull shape, a submarine hull shape with appendages and a full submarine shape with sail and appendages. It was found that the naked submarine hull is difficult to have the supercavitation covering the whole body. The sail and appendages can help supercavitation occurs earlier. Furthermore the effects of the supercavitation on the submarine and generation mechanism of the supercavitation is discussed based on the simulations.     

X105区块微幅度构造识别方法及应用

微幅度构造是油田开发中注水未波及的剩余油富集区。X105区块井间存在井网难以控制的微幅度构造,由于规模小,地震识别难。为提高识别精度,从3个方面开展了技术对策研究,以提高基础数据的准确性：开展提高微幅度构造成像精度的地震振幅高保真处理;创新了相位体约束层位解释方法提高砂岩组顶面识别精度;利用厚砂体井震匹配矛盾、深浅井震匹配矛盾分析法对微幅度构造进行筛选,去伪存真。应用上述方法,砂岩组顶面识别出断层控制和非断层控制两种成因类型的微幅度构造。在微幅度构造发育部位优选出未波及型和完善注采关系型两类剩余油挖潜区域,部署补充井实现了剩余油有效动用。     

磁场对含稀土铝锂合金断裂特征的影响

以含铈铝锂合金为研究对象，研究了磁场对含稀土铝锂合金时效过程的影响，从断裂特征及微观组织两方面分析了磁场作用规律。实验结果表明：未加磁场时，合金的断裂特征以理断裂为主；扁平晶粒厚度不匀，在磁场作用下，此合金的断裂特征与微观组织发生明显改观，随磁感应强度增强，合金主断裂面上准解理断裂特征减弱，同时二次裂纹增多，分层比较升高；扁平晶粒厚度变薄，尺寸趋于均匀。用少体物理理论，探讨了磁场对含稀土合金原子扩散过程的影响，为进一步研究稀土元素在磁场中的行为及其局域效应提供了一定的实验依据。     

Determination of acyclovir in horse plasma and body fluids by high-performance liquid chromatography combined with fluorescence detection and heated electrospray ionization tandem mass spectrometry

Two methods are presented for the determination of 'respectively' the plasma protein unbound and total concentration of acyclovir in horse plasma and body fluids: first, a liquid-liquid extraction was performed on plasma, combined with HPLC-fluorescence detection for the total plasma concentration; second a more sensitive method using high-performance liquid chromatography combined with heated electrospray ionization tandem mass spectrometry (LC-HESI-MS/MS) was described for plasma and for body fluids analysis. To obtain the unbound concentration of acyclovir in plasma, a simple deproteinization step using a Microcon filter was performed. Ganciclovir was used as an internal standard. Analysis was carried out on an Inertsil 5 ODS-3 column for the HPLC-fluorescence method. For the LC-HESI-MS/MS method a PLRP-S column was used. The limit of quantification (LOQ) for the total concentration was set at 50 and 2 ng mL(-1) for the HPLC-fluorescence method and the LC-HESI-MS/MS method, respectively. The limit of quantification for the unbound concentration was set at 5 ng mL(-1) and at 2 ng mL(-1) for body fluids. The methods were successfully used to perform pharmacokinetic and clinical studies in horses after intravenous and oral dosage of acyclovir and its prodrug valacyclovir.     

烟草叶肉原生质体再生壁形成的电镜研究

电镜观察表明,新分离的烟草叶肉原生质体表面光滑,在质膜外没有纤维状物质,内质网和高尔基体几乎没有发育:培养1天后,线粒体明显增加,粗面内质网和高尔基体沿质膜发育,质膜变得粗糙;2天后,质膜发生折皱,高尔基囊泡向质膜外分泌它的内含物;6天后,质膜表面出现明显松散分布的再生壁。在培养基中附加200 ppm香豆素处理,在培养1天后,质膜仍然光滑,未出现内质网和高尔基体;2天后,质膜开始变粗糙,内质网开始发育。试验表明,质膜、内质网、高尔基体在原生质体再生壁形成中起重要作用,并讨论了它们的可能作用。香豆素可能是在一定时同内,通过抑制质膜的活动和内质网、高尔基体的发育而抑制壁的再生。     

内置开孔隔墙高速铁路隧道列车车体压力波动特征

为研究内置开孔隔墙隧道内列车车体压力波动特征,基于有限体积方法的流体力学计算软件建立了非定常可压缩三维流动模型,对内置开孔隔墙高速铁路隧道内列车车体压力进行了计算分析。结果表明:隧道内置开孔隔墙后:①车体压力波形基本与无隔墙时一致,但波动程度加剧且出现有规律的周期振荡;②隔墙开孔间距和开孔面积对车体压力波的影响明显;③车体压力波幅值与车速成正相关关系,但其振荡周期与车速成反比;④相对于单车,列车对向运行时车体压力波明显增大,但两者的差值随着开孔间距的增大、开孔面积的减小和隧道长度的增加而减小。     

一种改进的基于人体静电冲击模型应力的瞬态功率模型

提出一种改进的基于人体静电冲击模型(Human Body Model, HBM)应力的瞬态功率模型。利用HSPICE仿真软件, 模拟MOS管遭受的HBM应力, 得到对应的等效直流电压。HBM电路的预充电电压与MOS管对应的等效直流电压值的散点图表明, 两者保持线性关系, 并通过拉普拉斯变化得到证明。与现有的瞬态功率模型相比, 改进后的模型降低了在HBM应力作用下的计算复杂度, 可以更加简便地从统计学上预测MOS管栅氧击穿的发生, 给HBM冲击作用下MOS管栅氧化层可靠性的评估提供参考。