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合成了一个无机,有机纳米复合物(MPYNN)0.14Mn0.93PS3,即有机氮氧自由基MPYNN(N-甲基吡啶阳离子自由基)的MnPS3夹层化合物.通过X-射线粉末衍射和红外光谱等对其结构进行了表征,根据其0.56 nm的层间距扩大值推测夹层化合物中的客体分子在层间采取了分子平面近乎垂直于主体层的排列方式.通过SQUID测试了所得到的夹层化合物的磁性,结果表明夹层化合物(MPYNN)0.14Mn0.93PS3在10 K以上具有顺磁特性,而在7 K时出现了一个明显的磁相变,表现出自发磁化. 相似文献
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The use of building materials containing naturally occurring radionuclides such as^40K,^238U,^232Th and their progeny, could lead to external exposures to the residents of such buildings. In this paper, a set of models are constructed to calculate the specific effective dose rates(the effective dose rate per Bq/kg of ^40K, the ^238U series,and the ^232Th series) imposed on residents by building materials with the MCNPX code. The effect of chemical composition, position concerned in the room and thickness as well as density of material is analyzed. In order to facilitate more precise assessment of indoor external dose due to gamma-emitting radionuclides in building materials,three regressive expressions are proposed and validated by measured data to calculate specific effective rates for40 K,the238U series and the232 Th series, respectively. 相似文献
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凋亡素是一种抗癌因子, 能以非p53依赖性途径诱导不同类型人肿瘤细胞的凋亡, 不受Bcl 2的抑制作用, 且对正常细胞不起作用。 根据凋亡素的肿瘤特异性, 可将其作为一种极具潜力的抗肿瘤生物制剂, 在人体内大量传递给肿瘤细胞, 有选择性地根除肿瘤细胞。 论述了凋亡素抗肿瘤细胞的作用机理, 并对其应用现状、 前景及进一步研究的主要问题予以简要评述。Apoptin is an anti cancer gene. It can induce p53 independent,Bcl 2 insensitive type of apoptosis in various human tumor cells,and fails to induce programmed cell death in normal cell. Because of having tumor specificity, apoptin can be transferred enough to tumor cell in vivo,selectly kill the tumor as a potential anti tumor biological preparation. In this paper, we provide a brief review on the anti cancer mechanism of apoptin, current status and application prospect, and the main issues in apoptin studies. 相似文献
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利用经典系综方法研究了不同椭偏率的反旋双色椭圆偏振(two-color elliptically polarized,TCEP)激光场中Ar原子非序列双电离(nonsequential double ionization,NSDI)的电子关联特性和再碰撞动力学.不同于反旋双色圆偏振激光场,反旋TCEP激光场不再具有空间对称性,返回电子主要从一个方向返回母离子,从而导致电子动量分布表现出很强的不对称性.数值结果显示随着椭偏率的增大,Ar原子NSDI的产量逐渐减小,并且电子对在椭圆偏振激光场长轴方向上的关联电子动量分布,从主要位于第一和第三象限的正相关逐渐演变为主要位于第二和第四象限的反相关.通过对不同特征时间的统计分析表明,随着椭偏率的增大,旅行时间和返回电子的重碰撞能量逐渐减小,而延迟时间却增大,这是电子对关联特性发生变化的主要原因.此外,进一步分析发现,无论是“短轨迹”还是“长轨迹”,椭偏率的增大都会使两个电子由同向出射逐渐转变为反向出射,这表明椭偏率和旅行时间都影响着电子的出射方向. 相似文献
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12C离子束的剂量学研究 总被引:1,自引:0,他引:1
研究了L-α-丙氨酸剂量计测量^12C离子辐射的剂量学特性,实验证明丙氨酸剂量计适用于^12C离子辐射的剂量学测量。另外,还研究了^12C离子照射人外周血诱发的染色体畸变(双着丝粒+着丝粒环)的剂量效应,在0-8.0Gy范围内拟合的最佳回归方程为Y=0.858503D+0.3615×10^-2D^2。Dosimetric characteristics of L-α-alanine dosemeter used for dosimetry of ^12C ion radiation have been studied. The experimental results indicate that the alanine dosemeter can be used to measure the ^12C ion radiation. In addition, dose effects of chromosome aberration dicentrics and cenric rings were studied after human peripheral blood being irradiated by ^12C ions; the best regression equation, Y = 0. 858 503D + 0. 361 5 ×10^-2D^2, was obtained within 8.0 Gy. 相似文献
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建立了唐古特铁线莲中齐墩果酸含量测定的HPLC方法。色谱条件:采用Phenomenex Luna C18(250 mm×4.6 mm,5μm),流动相:乙腈-0.2%H3PO4(35:65),流速:1 mL/min,柱温:室温(25℃),检测波长:205 nm。齐墩果酸在0.0233~0.7000 mg范围内呈良好的线性关系,线性回归方程为y=2E+06x+360803,R2=0.9917,回收率RSD为1.7%,并对青海省野生和栽培唐古特铁线莲中齐墩果酸进行了定量分析,结果显示前者平均值为0.1184%,后者平均值为0.0651%。方法可用以测定唐古特铁线莲中齐墩果酸的含量。 相似文献