基本放大电路微变等效电路的画法及动态参数分析

为降低学生学习晶体管放大电路的分析这一知识的难度,提出了画放大电路微变等效电路的"三线四点法",总结了微变等效电路的画图步骤,按此步骤可画出形式规范的电路并有利于继续分析计算动态参数。详细总结了动态参数的分析步骤和推导过程。为增加学习过程的可视性并激发学生的学习兴趣,应用Multisim电路仿真和设计软件仿真验证动态参数纯理论分析的正确性及可行性。本方法不仅适用于分析基本放大电路,也适用于分析其他较复杂的放大电路。     

水稻叶片低温应答蛋白质组学研究进展

近年来,人们利用高通量蛋白质组学技术分析了水稻(Oryza sativa L.)叶片低温应答过程中蛋白质组的动态变化特征,在水稻叶片中鉴定到了504种低温响应蛋白质.系统分析了这些蛋白质的丰度变化模式,综述了水稻叶片应对不同程度低温胁迫(5~15℃处理0~8 d)过程中参与光合作用、糖类与能量代谢、胁迫与防御、转录与蛋白质代谢、信号转导,以及膜与转运等过程中的蛋白质丰度变化特征,为全面理解水稻低温应答的分子网络调控机制提供了线索.     

基于改进模拟退火算法的木材类型识别方法

木材的优劣直接影响到木材的用途和价格,木材类型的准确识别尤为重要。在改进的模拟退火算法的基础上提出了木材类型特征选择方法FS-ISA,采用分类器的识别率作为评价指标,从14个灰度共生矩阵特征参数中选取最优特征参数组合,通过FS-ISA算法选取熵、对比度、角二阶矩、差异度、方差、逆差距等6个参数,组成最佳参数体系。结果表明,木材类型识别率最高达91.7%。     

四元Heusler合金Co_2V_(1-x)Cr_xAl的电子结构、磁性及半金属性研究

利用第一性原理计算方法,研究了L2_1型Heusler合金Co_2V_(1-x)Cr_xAl(x=0、0.25、0.5、0.75、1)的磁性、电子结构、半金属性及四方变形等。结果表明,随着Cr掺杂浓度的提高,合金总磁矩主要由Co的d电子贡献,总磁矩线性升高,符合Slater-Pauling规则,晶格常数线性减小,符合Vegard定律;此外,随着x的增加,费米面从临近导带底向靠近价带顶移动,能隙宽度增加,当x0.25时,合金具有半金属性。Co_2V_(0.5)Cr_(0.5)Al合金由于费米面位于自旋向下带带隙中部,抗原子无序能力强,在整个合金系列中半金属稳定性最佳,且在四方变形研究中,当c/a在0.92~1.07范围内时,该合金仍能保持稳定的半金属性。     

作物盐胁迫响应蛋白质组学研究

综述了近年来作物响应盐分胁迫蛋白质组学的研究进展．     

Divisional and hierarchical innervations of G. gecko’s toes to motion and reception

As a member of robot families, climbing robots have become one of the research hot-spots in the robotic field recently and Gekko gecko （G. gecko） has been broadly seen as an ideal model for climbing robot development. But for gecko-mimic robots, one of the key problems is how to design the robot＇s foot. In this paper, （1） high-speed camera recording and electrophysiological method are used to observe motion patterns of G. gecko＇s foot when it climbs on different oriented surfaces; （2） nerve innervations of gecko＇s toes to motion and reception are studied. It is found that the five toes of the G. gecko can be divided into two motion and reception divisions, and also its motion and reception are modulated and controlled hierarchically. The results provide important information and exclusive ideas for the foot design and control algorithm of gecko-mimic robots.     

Evidence of vacuolar compartmentalization of arsenic in the hyperaccumulator Pteris vittata

Pteris vittata can hyperaccumulate arsenic （As） to 〉1% of its dry weight without showing any signs of toxicity, indicating the existence of effective plant-internal detoxificaUon mechanisms. Although vacuolar compartmentalization is known to play an important role in heavy metal detoxification and tolerance, direct evidence of arsenic compartmentalization in this hyperaccumulator was lacking. Here we report the subcellular localization of As in the callus of P. vittata. The callus induced from gametophytes of P. vittata exposed to 0.2 mmol/L arsenate for 20 days were examined by directly isolating cell walls, protoplasts and vacuoles, and determining arsenic concentrations. Of the total As in the callus, about 94% was in the protoplast, and of that, 91% was present in the vacuoles, indicating that vacuoles are a major storage site for As in P. vittata. In addition, the changes in the chemical components of vacuoles were analyzed by Fourier transform infrared spectroscopy （FTIR）.     

论中医理论中的系统整体性思想

中医理论中蕴含着丰富的系统整体性思想。它不同于西方分析还原论的研究方法,坚持用整体论去分析研究人体疾病：不仅强调人体各个组成部分之间和人体与自然环境之间的系统整体性,而且对疾病进行综合考察,辨证施治,立方用药,进行全身心调节,力求达到整体最佳的目标。中医是系统整体性科学。     

东方龙虱鞘翅: 形态学及力学性能研究

研究了东方龙虱鞘翅的拓扑结构及其鞘翅生物材料的力学性能. SEM观测表明鞘翅横向截面和纵向截面结构相同, 是一种具 “桥墩” 状连接的空腔轻质结构, 由致密的黑色外表皮层和其下数十层几丁质纤维层平行、螺旋交织构成的内表皮层组成; 纳米压痕仪测得新鲜鞘翅外侧区域的硬度和弹性模量分别为0.31和6.13 GPa; 拉伸实验得到新鲜鞘翅横向和纵向的强度极限分别为169.2和194.5 MPa; 干燥鞘翅对应的强度极限为85.38和90.91 MPa, 新鲜鞘翅的强度是干燥鞘翅值的2倍; 结果表明甲虫鞘翅是一种力学性能呈现拓扑分布规律的轻质生物复合材料, 该研究为航空航天材料的轻质结构的设计提供了生物学的参考.