排序方式: 共有23条查询结果,搜索用时 31 毫秒
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脂质体导向给药治疗缺血性心脏病的可行性研究(Ⅰ) 总被引:2,自引:0,他引:2
本工作在离体大鼠心肌细胞、离体灌流大鼠和家兔心脏模型上,对脂质体作为药物载体导向治疗缺血性心脏病的可行性进行了基础研究。结果表明,心肌细胞可通过融合(Fusion)、内吞(Endocytosis)、吸附(Adsorption)和磷脂分子交换(Exchange)四种方式与脂质体相互作用。细胞摄取脂质体的方式主要取决于脂质体的理化性质。缺氧改变了心肌细胞对脂质体的摄取方式并增加其摄取能力。缺血心肌组织对脂质体、尤其对带正电荷脂质体的摄取显著增加。其摄取量按序为缺血-再灌注区>梗塞边缘区>非缺血区>梗塞区。上述实验结果提示:脂质体作为药物载体可将药物输送到缺血心肌组织和心肌细胞内。 相似文献
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Characteristics of single- and multi-finger mesa InGaAs/InP double heterojunction bipolar transistors (DHBTs) are compared. The current gain decreases with the increasing number nf of the emitter fingers due to the mutual thermal interaction between the fingers. The Kirk current can be as high as 150mA for four-finger DHBT. No degradation of the peak of the current gain cutoff frequency ft is found for multi-finger DHBTs. The peak of the maximum oscillation frequency fmax decreases with an increase of nf due to the increasing parasitic resistance of the base. The results are very helpful for applications of the common-base DHBTs in power amplifiers operating at very high frequencies. 相似文献
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基于多尺度总体最小二乘的图像去噪 总被引:3,自引:1,他引:2
提出了一种基于多尺度总体最小二乘的图像去噪算法.采用平稳小波变换对噪音图像进行分解,分别对各个分解层的高频子带,通过总体最小二乘算法估计信号小波系数;并且考虑到不同尺度小波系数之间的相关性,将尺度相关性约束到总体最小二乘算法中,进而准确估计各高频子带信号小波系数,再由估计的信号小波系数通过小波逆变换得到去噪图像.实验结果表明,考虑尺度间相关性的总体最小二乘平稳小波变换图像去噪算法能有效去除图像噪音,在信噪比和视觉质量上有了较大改善. 相似文献
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Growth condition optimization and mobility enhancement through inserting AlAs monolayer in the InP-based In_xGa_(1-x)As/In_(0.52)Al_(0.48)As HEMT structures 下载免费PDF全文
The structure of In P-based In_xGa_(1-x) As/In0.52Al0.48 As pseudomorphic high electron mobility transistor(PHEMT)was optimized in detail.Effects of growth temperature,growth interruption time,Si δ-doping condition,channel thickness and In content,and inserted Al As monolayer(ML) on the two-dimensional electron gas(2DEG) performance were investigated carefully.It was found that the use of the inserted Al As monolayer has an enhancement effect on the mobility due to the reduction of interface roughness and the suppression of Si movement.With optimization of the growth parameters,the structures composed of a 10 nm thick In0.75Ga0.25 As channel layer and a 3 nm thick Al As/In0.52Al0.48 As superlattices spacer layer exhibited electron mobilities as high as 12500 cm~2·V-1·s~(-1)(300 K) and 53500 cm~2·V~(-1_·s~(-1)(77 K) and the corresponding sheet carrier concentrations(Ns) of 2.8×10~(12)cm~(-2)and 2.9×1012cm~(-2),respectively.To the best of the authors' knowledge,this is the highest reported room temperature mobility for In P-based HEMTs with a spacer of 3 nm to date. 相似文献
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提出了一种基于多尺度总体最小二乘的图像去噪算法.采用平稳小波变换对噪音图像进行分解,分别对各个分解层的高频子带,通过总体最小二乘算法估计信号小波系数|并且考虑到不同尺度小波系数之间的相关性,将尺度相关性约束到总体最小二乘算法中,进而准确估计各高频子带信号小波系数,再由估计的信号小波系数通过小波逆变换得到去噪图像.实验结果表明,考虑尺度间相关性的总体最小二乘平稳小波变换图像去噪算法能有效去除图像噪音,在信噪比和视觉质量上有了较大改善. 相似文献
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较为系统地研究了掺碳p型GaAs和InGaAs的金属有机物分子束外延(MOMBE)生长特性和电学特性。结果表明,衬底温度和分子束强度等生长条件对于样品的生长速率、空穴浓度及In组分含量等具有较大的影响,在InGaAs的生长中这种影响更为强烈。根据对实验结果的分析,可以认为,作为分子束源之一的TMGGa(CH3)3,trimethylgallium,三甲基镓的分解状态与生长条件的相关性,是引起生长速率和空穴浓度等变化的主要因素。
关键词: 相似文献
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