Synthesis,Crystal Structure and MMCT Property of a New Mixed-valence Cyanide-bridged Binuclear Complex

A new mixed-valence cyanide-bridged complex, Br3Fe(μ-NC)RuBr(dppm)2(dppm = bis(diphenylphosphino)methane), was obtained through the reaction between trans-(dppm)2ClRuCN and FeBr3. Its crystal structure was characterized. Electronic absorption spectra indicate the existence of metal-to-metal charge transfer(MMCT) and this complex is Class Ⅱ mixed valence complexes according to the classification of Robin and Day. Magnetic analysis shows it is paramagnetic.     

傅里叶叠层显微术的照明光强校正研究北大核心CSCD

傅里叶叠层显微术(FPM)是一种新型的计算显微成像技术,FPM与传统显微术照明方式不同,常采用可编程LED阵列进行不同角度照明,而LED灯珠发射光强与角度有关,随角度增大光强迅速减弱,不同角度照明光强不能保证一致,导致重建图像质量下降。因此,在进行相位迭代反演计算过程中,需要对不同角度照明拍摄的图像进行光强校正。介绍了不同角度照明光强不均一的原因,通过数值模拟,探讨了对不同角度照明光强进行校正的必要性,最后给出了物理上光强校正的实验结果。     

应用于无线传感器网络的射频发射机电路

设计了符合工业无线传感器网络WIA-PA标准的发射机电路.采用中频转换电路控制模拟中频信号的偏置及幅度以满足混频器的输入范围.采用正交双平衡混频器结构进行上变频,通过在固定电容上串联可调电容,拓宽了混频器的选频范围.后级接可编程功率预放大器,产生差分的功率输出信号,以满足不同传输距离的要求.发射机电路在0.13 μm CMOS工艺下进行流片.通过与WIA-PA基带芯片联合调试,测试结果表明,设计的直接上变频发射机芯片的误差矢量幅度(EVM)小于13.5％,镜像抑制达到34 dBc,很好地满足了无线传感器网络节点的应用需求.     

Syntheses and Crystal Structures of a Series of Coordination Complexes Derived from the Fluorescein Ligand

Solvothermal reaction of lanthanide(Ⅲ) salts with fluorescein (2-(6-hydroxy3-oxo-3H-xanthen-9-yl)benzoic acid) led to a series of new coordination polymers {[Ln(C 20 H 11 O 5)(C 20 H 10 O 5)(H 2 O)]·DMF} n (Ln=Er,Eu,Gd,Tb,Tm,Yb).The PXRD patterns of the complexes indicate they are isomorphous.The structure of complex {[Er(C 20 H 11 O 5)(C 20 H 10 O 5)(H 2 O)]·DMF} n has been determined by single-crystal X-ray diffraction,revealing a 2D framework in which DMF molecules were filled between the layers.The crystal structure belongs to the triclinic system,space group P1,with a=12.107(4),b=12.232(4),c=13.273(4),α=68.005(7),β=88.024(11),γ=77.451(8)°,V=1776.7(9) 3,Z=2,D c=1.720 g/cm 3,μ=2.434 mm-1,F(000)=918,R int=0.0584,T=293(2) K,the final R=0.0621 and wR=0.1501.     

标准化组织的知识产权政策(2)

同上述国际标准化组织的知识产权政策相比，以私权为基础的标准化组织的知识产权政策要复杂和完备的多。因为他们要设定使标准化组织能及时有效运作的全部工作规程，其中包括如何获得许可、如何对外技术许可等等内容，其工作制度的设定还要满足一些政府职能部门如反垄断审查部门的要求。因此，以私权为基础的标准化组织的知识产权政策比较详细和完备，但同时在具体细节规定上又各不相同。     

157W准连续AlGaAs/GaAs激光二极管线列阵

通过优化设计量子阱结构和列阵结构,减小腔面光功率密度,避免器件腔面灾变损伤,得到1cm AlGaAs/GaAs激光二极管线列阵,在热沉温度21℃,脉冲宽度200μs,重复频率100Hz时,输出峰值功率达157W。     

A digitally controlled PWM/PSM dual-mode DC/DC converter

A digitally controlled pulse width modulation/pulse skip modulation(PWM/PSM) dual-mode buck DC/DC converter is proposed.Its operation mode can be automatically chosen as continuous conduction mode (CCM) or discontinuous conduction mode(DCM).The converter works in PSM at DCM and in 2 MHz PWM at CCM.Switching loss is reduced at a light load by skipping cycles.Thus high conversion efficiency is realized in a wide load current.The implementations of PWM control blocks,such as the ADC,the digital pulse width modulator(DPWM) and the loop compensator,and PSM control blocks are described in detail.The parameters of the loop compensator can be programmed for different external component values and switching frequencies, which is much more flexible than its analog rivals.The chip is manufactured in 0.13μm CMOS technology and the chip area is 1.21 mm~2.Experimental results show that the conversion efficiency is high,being 90%at 200 mA and 67%at 20 mA.Meanwhile,the measured load step response shows that the proposed dual-mode converter has good stability.     

无标记快速检测蝇毒磷的表面等离子体共振生物传感器

针对现有农药检测方法操作复杂、仪器贵重、不利于现场快速检测等问题,将自行研制的便携式表面等离子体共振生物传感器应用于高毒性农药蝇毒磷的检测,采用直接法检测抗体。提出连续检测法,对质量浓度分别为500、200、100、50、0 mg/L的蝇毒磷小分子样品进行了连续检测实验。通过实验证明了该装置和方法的可行性。基于表面等离子体共振的无标记蝇毒磷检测方法简单,仪器便携,操作简便,可实现现场快速检测。     

Magnetic properties of Nd0.5Pb0.5-xSrxMnO3 materials

The structure and magnetic properties of Nd0.5Pb0.5-xSrxMnO3 (0≤x≤0.4) manganites were systematically investigated. Significant changes in Curie temperature and metal-insulator (MI) transition temperature of the samples were observed. All samples exhibited a transition from paramagnetic semiconducting to ferromagnetic metallic state.Curie temperature Tc and the MI transition temperature Tp increased with increasing Sr content. We attributed these behaviours to the enhancing of both the double exchange mechanism and the Jahn-Teller electron-phonon coupling.     

La0.67Ca0.33MnO3单晶中Fe的掺杂提高本征磁电阻率和激活能的研究

La_0.67Ca_0.33MnO₃ and La_0.67Ca_0.33Mn_0.96Fe0.04O₃单晶的磁性和磁电阻特性。由于缺少晶粒间界，磁场对于自旋涨落的抑制作用更加明显，所以单晶中的磁电阻率比多晶的提高了两个数量级。通过Fe的掺杂，在40×10⁵A/m的磁场下，磁电阻率从3400%进一步提高到了17600%。通过对居里温度以上电阻率的小极化子模型拟和的结果，我们看到随着Fe的掺杂，激活能被提高。磁极化子激活能的增大可以更加局域电子，这可能是在Fe掺杂单晶中本征磁电阻率进一步提高的主要原因。