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A transplantable myelocytic leukemia model of LACA mice, designated by the name of L_(801), was established by intravenous injection of spleen cell suspension from mice with radiation-induced myclocytic leukemia into mice of the same strain.Until now, for more than three years, the L_(801) has maintained stable and rapid growth and has been reproduced for over 130 serial passages. The incidence of leukemia in inoculated animals was approximately 100% and mean survival time was 10.9±2.1 days. The L_(801) is of myelocytic type which has been determined by cytological, cytochemical, pathological and ultrastructural observations. Its karyotype was hypodiploid, characterized by modal number of 39, loss of Y chromosome and an abnormal huge marker chromosome. The cell cycle duration of the L_(801) was 16 h. C-type viral particles were observed under the electron-microscope. The L_(801) was sensitive, to varying extents, to various anti-tumor agents.We presume that the L_(801) is a useful tool in studies on me 相似文献
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Strain Induced Nanopillars and Variation of Magnetic Properties in La_(0.825)Sr_(0.175)MnO_3/LaAlO_3 Films 下载免费PDF全文
To investigate the process of strain relaxation and resultant variation of microstructure and magnetic properties,low-doped La_(0.825)Sr_(0.175)MnO_3 epitaxial films with different thicknesses are deposited on LaAlO_3 substrates and strain induced nanopillars are discovered inside the La_(0.825) Sr_(0.175)MnO_3 film. Perpendicular oriented nanopillars mainly exist below 30 nm and tend to disappear above 30 nm. The distribution of nanopillars not only induce the variation of lattice parameters and local structural distortion but also lead to the deviation of easy magnetization axis from the perpendicular direction. Specifically, the out-of-plane lattice parameters of the film decrease quickly with the increase of the thickness but tend to be constant when the thickness is above 30 nm. Meanwhile, the variations of magnetic properties along in-plane and out-of-plane directions would also decline at first and they then remain nearly unchanged. Our work constructs the relationship between nanopillars and magnetic properties inside films. We are able to clearly reveal the effects of inhomogeneous strain relaxation. 相似文献
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为提高机器人移动的灵活性和机动性,使机器人到任意位置均沿直线行走并改变姿态,需在传统的两轮驱动底盘上增加驱动轮,本文主要针对四轮驱动全向底盘的控制方法进行研究。本文对四轮驱动全向底盘进行运动学分析并建模,得到了控制系统传递函数,并进仿真验证;对四轮驱动全向底盘进行了动力学建模,分析了如何避免出现“打滑”现象;导航方式采用了经济、精度较高的全向码盘导航方式;控制上采用闭环控制,加入前置探测点和超前校正环节,并且考虑了实际过程中机体的加减速问题。实验结果表明,提出的控制方法可以使四轮驱动全向底盘实现预设功能,并且具有较高的控制精度,研究内容对机器人的灵活移动有着十分重要的意义。 相似文献
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精细结构常数α,既可以描述能级的精细结构,又能描述能级的“粗略“结构。其物理意义是什么?本通过带基本电荷粒子的电磁相互作用能与粒子静能之比,导出常数α。并指出α是表示电磁耦合强弱的一个普适常数。可以叫做电磁常数。 相似文献
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结合传统有界波模拟器和辐射波模拟器的特点,采用新型双锥-线栅型平板天线结构,设计了一台水平极化有界波电磁脉冲模拟器。通过电磁仿真和实验测试,对模拟器的辐射特性和场均匀性进行了研究。仿真结果和实测结果基本一致。结果表明,模拟器能产生包含地面反射的水平极化电磁脉冲环境,波形满足上升沿(2.5±0.5) ns、半高宽(23±5) ns的高空电磁脉冲标准要求。模拟器使用灵活机动,能在不小于5 m×3 m×2 m工作空间内产生峰值场强不小于50 kV/m的6 dB均匀场,也能在降低测试场强时提供更大的工作空间。 相似文献
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膜污染是制约纳滤技术在废水处理和回用应用的主要问题。吸附法和混凝法是废水预处理的常用方法,可以有效降低污水的浊度和色度物质,保障后续膜工艺的稳定运行。但由于不同类型废水中污染物含量和组成特点各不相同,对活性炭吸附或混凝处理的性能和效率有显著的影响,需要针对性的筛选和优化来选取合适的预处理工艺参数条件。本研究采用4种活性炭(A-D型)和4种混凝剂(FeCl3,Al2(SO4)3,PACla和PAClb)对城市污水、制药废水和纺织废水的预处理效率进行优化。结果表明,B型投加量为30 g·L-1对城市污水处理效率最高,对制药废水D型投加量为20 g·L-1是更可取的,针对纺织废水D型投加量为30 g·L-1时是最合适的选择。混凝预处理方法下,城市污水和纺织废水使用0.5 mmol·L-1的PACla效果最佳,而制药废水则是投加0.5 mmol·L-1的FeCl3效果更好。通过对优化后的吸附剂和混凝剂预处理效果的比较,表明采用吸附剂和混凝剂相结合的方法可以获得最佳的预处理效果,且成本更经济合理。 相似文献
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本文用脾细胞悬液给同系成年小鼠尾静脉接种建立起来的小鼠可移植性粒细胞白血病瘤株,命名为L_(801)。三年来已传130余代,瘤株生长稳定,接种成功率接近100%,平均存活时间为10.9± 2.1d.根据细胞学、细胞化学、病理学和超微结构检查,证明本瘤株为粒细胞白血病.白血病细胞染色体检查为亚二倍体,众数为39条,y染色体丢失和存在一个大的标记染色体;细胞周期为16 h;电子显微镜观察可见C型病毒颗粒;对各类抗癌药物均有不同程度的敏感性.因此,L_(801)瘤株的建立将对辐射致癌机理、辐射与病毒致癌之间关系的研究,对抗肿瘤药物筛选和实验肿瘤治疗的研究均有重要意义。 相似文献
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