Identification of transverse spin currents in noncollinear magnetic structures

In this Letter we construct a spinor transport theory and derive the equations of motion for the distribution functions for currents in noncollinear magnetic multilayers. We find the length scale which characterizes the transverse spin current is of the order of 3 nm for a ferromagnetic 3d transition metal such as Co; this alters one's prediction of the spin torque generated for free magnetic layers less than 3 nm. In the limit of large exchange splitting we reproduce the results previously found for spin currents across noncollinear multilayers inasmuch as there are no transverse spin currents in the layers themselves in this limit.     

双热源空调-热水器一体机冬季制热的实验研究

冬季室外温度低时,空气源热泵系统的蒸发器会结霜,使系统COP降低。所设计的空调-热水器一体机可以制冷、制热、一年四季提供生活用热水。冬季室外温度低时,用太阳能加热后的水作为热泵的低温热源,可以提高热泵的效率。分别用空气源蒸发器和水源蒸发器独立工作使系统给房间制热,实验结果发现水源蒸发器工作时系统的COP平均值为3.56,空气源蒸发器工作时的COP平均值为2.51。     

Mechanochemical synthesis of Na-β/β″-Al2O3

Na-β/β″-alumina powders were synthesized by a mechanochemical processing. The influences of mechanical activation in the phase composition and microstructure of the final powders were investigated. Fine Na-β/β″-alumina powders were obtained at a lower temperature than that of a conventional solid-state reaction processing. The mechanism of the mechanical activation was studied. It was found that mechanical activation greatly affected the calcining process and phase composition of the precursory powders.     

Optimizing two-photon fluorescence of Coumarin dye by combined temporal–spatial pulse shaping

Two-photon fluorescence (TPF) process is an important research subject and can be optimized by pulse shaping techniques. In addition to temporal femtosecond pulse shaping by spectral phase modulation, we take into account of spatial configuration in the shaping process. The TPF of Coumarin 500 increases 40% with this additional modulation step. This spatial modulation results in not only transverse spatial profile variation but also effect of temporal redistribution at focus. We show that this spatial modulation is an important dimension for pulse shaping and optimization for TPF.     

脊形掺铒Al2O3光波导放大器级联特性的模拟计算

利用有限元法分析了脊形掺铒Al₂O₃光波导放大器内信号光和抽运光的场模式分布、速率方程求解铒离子五能级系统的粒子数分布.数值模拟了光波导净增益与信号光功率的关系和多个放大器级联的净增益特性.结果表明：级联系统存在着净增益亏损.低掺铒浓度的光波导作前级放大器的组合方式,级联系统总净增益最大.     

气相色谱-质谱法测定热塑性弹性体中的多环芳烃

建立了一种简单、准确的测定热塑性弹性体中16种多环芳烃(PAHs)的气相色谱-质谱(GC-MS)方法。考察了样品制备、萃取溶剂、萃取方法、时间以及温度对厂家制备的阳性热塑性弹性体样品中PAHs提取效率的影响,确定了萃取条件和方法。样品经甲苯超声萃取、浓缩后用环己烷溶解、二甲亚砜液液萃取净化后采用GC-MS进行分析,内标法定量。通过对不同材质阳性热塑性弹性体样品的加标回收、精密度试验等对建立的方法进行评价,16种PAHs的平均回收率为70%～117%,精密度为0.2%～10.8%。该方法适合于热塑性弹性体中PAHs的测定。     

Ftir Studies on LB Film of Amphiphile with Schiff Base as Headgroup and Its Copper Complex

Two different ways to form monolayers and LB films (surface film and subphase film) of the complex have been used, where a novel amphiphile containing Schiff base as a headgroup was used as a ligand. the monolayer behavior at the air/water interface was characterized by π-A isotherms and two-dimensional molecular orientation of alkyl chains in LB films and thermal stability were measured by polarized and variable temperature FTIR transmission spectra, indicating that the LB film of the novel amphiphile and its copper(II) complex are very stable as well as stearic acid. Because incorporating the metal ion into the monolayer makes it more condensed, thermal stability of the LB film was enhanced. as can be compared from their structure and properties, subphase films are superior to surface films.     

CO_2激光边带光谱仪用于SF_6分子v_3带Q支吸收谱的研究

用绝对频率精度优于1.2MHz的CO_2激光边带光谱仪记录了SF_6分子v_3带Q支的多普勒受限吸收谱,光谱范围在CO_2激光10P(16)支线中心两侧,距支线中心8.0～12.4 GHz。用内插法以<6MHz的均方误差测量了百余条跃迁谱线的频率,并标识出Q_Z、Q_R、Q_X、Q_W、Q_A等亚支的谱线,量子数J从26到83。用最小二乘法拟合实验数据得到了v_3带的部分光谱常数。     

利用B样条曲线设计指纹图像滤波模板和快速指纹特征匹配算法

在指纹图像识别过程中,指纹图像的滤波去噪音二值化和指纹特征的匹配是最关键的两个部分.本文针对这两部分的算法设计进行分析和改进,介绍利用B样条造型来设计指纹滤波模板的方法和基于基准点附近的拓扑结构进行快速特征匹配的算法.并且利用改进后的指纹特征匹配算法,在样本指纹库中进行实验,结果表明该算法大大提高了指纹特征匹配的效率和准确性.     

Carbene triel bonds between TrR3 (Tr = B,Al) and N-heterocyclic carbenes

The carbene triel bond is predicted and characterized by theoretical calculations. The C lone pair of N-heterocyclic carbenes (NHCs) is allowed to interact with the central triel atom of TrR₃ (Tr = B and Al; R = H, F, Cl, and Br). The ensuing bond is very strong, with an interaction energy of nearly 90 kcal/mol. Replacement of the C lone pair by that of either N or Si weakens the binding. The bond is strengthened by electron-withdrawing substituents on the triel atom, and the reverse occurs with substitution on the NHC. However, these effects do not strictly follow the typical pattern of F > Cl > Br. The TrR₃ molecule suffers a good deal of geometric deformation, requiring on the order of 30 kcal/mol, in forming the complex. The R(C···Tr) bond is quite short, for example, 1.6 Å for Tr = B, and shows other indications of at least a partially covalent bond, such as a high electron density at the bond critical point and a good deal of intermolecular charge transfer.