含手性膦配体的铑化合物的NMR研究

利用1D和2D NMR技术.对含有手性膦配体的铑化合物trans-((3-MBPA)₂Rh(CO)Cl)(1)和trans-((2-MBPA)₂Rh(CO) Cl)(2),进行¹H和¹³C NMR谱分析,归属了所有的¹H和¹³C NMR谱线,并根据磷和铑的偶合常数及羰基与磷,铑的偶合常数确定它们是反式构型.     

试论物理教学中的美育

从物理学内容的表现形式、物理学的研究方法、物理学的发展趋势等方面论述了物理学中美的因素；从教学过程、教学方法、教态等方面探讨了物理教学中的审美教育。     

LIMITED TRYPTIC DIGESTION OF LEUCYL-tRNA SYNTHETASE AND CHARACTERIZATION OF ITS ACTIVE FRAGMENT

Leucyl-tRNA synthetase (LeuRS, EC 6.1.1.4) from E. coli underwent limitedproteolysis by trypsin which cut off 6K peptide and converted the intact LeuRS into a 96K fragment. The truncated enzyme retained the PPi exchange activity with the same kinetic parameters as those of native LeuRS but lost the tRNA~(Leu)charging, binding and other tRNA~(Leu)-related activities. N-terminus analysis showed that the 6K peptide was located at the C-terminus of LeuRS. This small part played a crucial role in tRNA~(Leu) binding. Our results suggest that the two activities, PPi exchange and tRNA charging are independent of each other and correspond to different structural regions of LeuRS. The C-terminal region might be the tRNA~(Leu)binding site of LeuRS.     

切披萨

正一个星期六早上,妈妈买来一个圆圆的大披萨。闻着那香喷喷的味道,我的口水都快流出来了。我拿起刀准备切披萨,但妈妈拦住我,笑着说:"这个披萨切1刀可以分成2块,切2刀最多可以分成4块,那么,切3刀最多可以分成几块呢?"我想了想,自信地回答:"切3刀最多可以分成6块,我画给你看。"     

噪音信号对夜间对流层臭氧探测准确度的影响

本文探讨在背景噪音影响下,差分吸收激光雷达测量臭氧的不确定性:背景噪音对臭氧浓度廓线的影响正比于背景噪音强度、强吸收波长和弱吸收波长的回波信号强度比.理论计算结果表明:合适的回波信号强度比可以使激光雷达背景信号对夜间臭氧探测浓度的影响变得非常小,可以忽略不计.实验结果表明:用波长对(280 nm,285 nm)对大气臭氧进行观测时,适当调节两波长回波信号强度比为0.96时,背景信号对臭氧浓度探测的影响小到可以忽略的程度.模拟分析和实验观测结果相接近,证实了理论推算的合理性.在背景噪音强度未知的情况下,通过调整强吸收和弱吸收两波长的激光脉冲的能量,在示波器上得到适合的回波信号强度比值,可以抑制背景噪音信号对臭氧探测结果的影响,确保夜间臭氧测量的准确性.     

相依样本下移动平滑过程的极限性质(英文)

定义平滑过程{Xn=∑i=-∞∞aiYi+n;n≥1},其中{ai;-∞i∞}是绝对可和的实数序列,{Yi;-∞i∞}是独立同分布并且-ρ-混合的双边无限序列.在{Yi;-∞i∞}均值为零、方差有限等条件下,证明移动平滑过程的收敛性,推广了李和张的结论.     

聚苯胺基反射型柔性电致变色器件的制备与工艺研究

采用化学法合成聚苯胺(PANI),在柔性不锈钢丝网上进行涂覆,成功制备了反射型柔性变色器件.测试并获取了不同电位下(即不同的掺杂态)的紫外-可见光全反射光谱,比较确定了该变色器件合适的使用电压为+0.7V和-0.6V.并在选定的使用电压下对变色器件进行测试,讨论了工作电极上PANI用量、电解质层用量和离子储存层用量对变...     

用于光腔衰荡光谱测量的多支路掺铒光纤飞秒光梳系统

报道了用于光腔衰荡光谱测量的多支路掺铒光纤飞秒光梳系统.该系统以“9”字型全保偏掺铒飞秒光纤激光器为激光源.利用自制的锁相环电路,获得的重复频率和载波包络相移频率秒级稳定度分别为5.85×10^–13和4.95×10^–18.为了满足CO, CH₄等分子吸收光谱测量,利用啁啾放大和非线性光谱展宽技术,采用多支路结构,将飞秒光梳直接输出光谱由1500—1600 nm分别扩展至8个目标波长(1064, 1083, 1240, 1380, 1500,1600, 1750和2100 nm)处,各目标波长处的单模功率均大于300 n W,满足光腔衰荡光谱测量实验的需求.     

Vacuum current-carrying tribological behavior of MoS2-Ti films with different conductivities

Current-carrying sliding is widely applied in aerospace equipment, but it is limited by the poor lubricity of the present materials and the unclear tribological mechanism. This study demonstrated the potential of MoS₂-based materials with excellent lubricity as space sliding electrical contact materials by doping Ti to improve its conductivity. The tribological behavior of MoS₂-Ti films under current-carrying sliding in vacuum was studied by establishing a simulation evaluating device. Moreover, the noncurrent-carrying sliding and static current-carrying experiments in vacuum were carried out for comparison to understand the tribological mechanism. In addition to mechanical wear, the current-induced arc erosion and thermal effect take important roles in accelerating the wear. Arc erosion is caused by the accumulation of electric charge, which is related to the conductivity of the film. While the current-thermal effect softens the film, causing strong adhesive wear, and good conductivity and the large contact area are beneficial for minimizing the thermal effect. So the moderate hardness and good conductivity of MoS₂-Ti film contribute to its excellent current-carrying tribological behavior in vacuum, showing a significant advantage compared with the traditional ones.