An interconnecting bus power optimization method combining interconnect wire spacing with wire ordering

On-chip interconnect buses consume tens of percents of dynamic power in a nanometer scale integrated circuit and they will consume more power with the rapid scaling down of technology size and continuously rising clock frequency, therefore it is meaningful to lower the interconnecting bus power in design. In this paper, a simple yet accurate interconnect parasitic capacitance model is presented first and then, based on this model, a novel interconnecting bus optimization method is proposed. Wire spacing is a process for spacing wires for minimum dynamic power, while wire ordering is a process that searches for wire orders that maximally enhance it. The method, i.e., combining wire spacing with wire ordering, focuses on bus dynamic power optimization with a consideration of bus performance requirements. The optimization method is verified based on various nanometer technology parameters, showing that with 50% slack of routing space, 25.71% and 32.65% of power can be saved on average by the proposed optimization method for a global bus and an intermediate bus, respectively, under a 65-nm technology node, compared with 21.78% and 27.68% of power saved on average by uniform spacing technology. The proposed method is especially suitable for computer-aided design of nanometer scale on-chip buses.     

Controlled phase gates based on two nonidentical quantum dots trapped in separate cavities

We propose a scheme for realizing two-qubit controlled phase gates on two nonidentical quantum dots trapped in separate cavities. In our scheme, each dot simultaneously interacts with one highly detuned cavity mode and two strong driven classical fields. During the gate operation, the quantum dots undergo no transition, while the system can acquire different phases conditional on different states of the quantum dots. With the application of the single-qubit operations, two-qubit controlled phase gates can be realized.     

固液界面光催化裂解水的理论进展

二氧化钛纳米颗粒作为一种光催化剂,目前已经得到了广泛的应用,但是对于光催化反应的理解,尤其是在原子水平上,还明显不足,如TiO₂纳米颗粒的几何结构与光催化反应活性的构效关系。本文主要介绍了我们课题组在TiO₂裂解水的一些理论研究进展。通过周期性密度泛函以及周期性连续介质模型的理论计算,我们研究了水析氧反应(OER)的机理,得出了反应的决速步骤是失去第一个质子的过程,同时研究了不同纳米颗粒对该决速步骤的影响。研究指出,TiO₂纳米颗粒的热力学平衡构型在1-30nm内会受到其颗粒尺寸的显著影响;尖的TiO₂纳米颗粒比扁的颗粒具有更高的OER反应活性。综合以上两个因素,最终导致了光催化反应的形态依赖性。     

Electromagnetic absorption properties of flowerlike cobalt composites at microwave frequencies

In this work,we report the electromagnetic absorption(EMA) properties of composites consisting of micrometersized cobalt with flowerlike architecture synthesized by a facile hydrothermal reduction method.Compared with the conventional spherical Co-paraffin composites,the flowerlike Co-paraffin composites are favorable with respect to EMA performance in the low frequency region,ascribing interfacial polarization loss and Ohmic loss to the improvement in the impedance match.     

Ion pickup by intrinsic low-frequency Alfven waves with a spectrum

<正>Ion pickup by a monochromatic low-frequency Alfven wave,which propagates along the background magnetic field,has recently been investigated in a low beta plasma(Lu and Li 2007 Phys.Plasmas 14 042303).In this paper, the monochromatic Alfven wave is generalized to a spectrum of Alfven waves with random phase.It finds that the process of ion pickup can be divided into two stages.First,ions are picked up in the transverse direction,and then phase difference(randomization) between ions due to their different parallel thermal motions leads to heating of the ions.The heating is dominant in the direction perpendicular to the background magnetic field.The temperatures of the ions at the asymptotic stage do not depend on individual waves in the spectrum,but are determined by the total amplitude of the waves.The effect of the initial ion bulk flow in the parallel direction on the heating is also considered in this paper.     

间甲基苯甲酸的THz时域光谱

利用THz时域光谱技术测量了间甲基苯甲酸在0.2 ~1.8 THz频率范围内的振动光谱,结合密度泛函理论计算的振动光谱,对观测到的强振动吸收峰进行了指认. 比较不同的芳香化合物的振动光谱,间甲基苯甲酸分子的特征振动峰与其他芳香化合物的振动特征峰在0.2~1.8 THz频率范围内明显不同.     

超短脉冲激光烧蚀金属靶热分布的数值解与解析解

研究了超短脉冲激光烧蚀靶材的整个过程,对描述超短脉烧蚀过程热行为的双温度方程进行了分析简化,得出了超快激光烧蚀金属材料的解析解. 以铜靶材为例,对双温度模型的数值解与解析解做了对比分析,得到了靶材温度随时间和深度的变化规律,结果显示解析解的计算结果比较好的符合了数值解的计算结果.     

利用高温超导直流量子干涉器件进行10$lt;sup$gt;-6$lt;/sup$gt; T量级磁场下核磁共振的研究

研究了水样品在10^-6 T量级磁场下的核磁共振谱.核磁共振信号由一个工作在液氮温度的高温超导直流量子干涉仪记录,测量在一个简易磁屏蔽室中进行.在7—70 μT的磁场范围内都观察到了15 ml水样品的核磁共振信号.相应的^1H的核磁共振频率为300—3000 Hz.在实验中获取的单次测量信噪比约为4,通过对信号的100次平均,信噪比可达到约40.进一步讨论了剩余磁场、预极化时间和采样时间对结果的影响.最后用数字滤波之后平均的方法初步得到了时域的自由感应衰减信号. 关键词： 超导量子干涉仪 核磁共振     

AlAs相变及热动力学性质的第一性原理研究

利用基于密度泛函理论的全势能线性糕模轨函法研究了闪锌矿（B3）,NiAs（B8）和岩盐（B1）结构的AlAs的相变、结构性质以及热动力学性质.对B3-B8和B3-B1结构的能量体积曲线做公切线,得到了B3→B8相变压力为5.44 GPa,并预测到B3→B1相变压力为6.46 GPa.同时计算了高压下B8相的结构性质,结果显示当V/V₀≈0.7—1.05时,c/a基本保持恒定（仅有约 0.2%的波动）;当V/V₀≈0.4—0.7,c/a随着V/V₀的减小而近似线性地增大.通过状态方程拟合,得到了AlAs的相对体积V/V₀与压强P的函数关系,B8相的状态方程与实验结果符合很好.最后利用准谐德拜模型得到了AlAs的体弹模量B随压力P的变化关系以及不同压强下热容C_V与温度T的关系. 关键词： 相变 热力学性质 第一性原理     

两种三唑类杀菌剂的拆分研究

将纤维素-三（3,5-二甲基苯基氨基甲酸酯）（CDMPC）涂敷于自制的球形氨丙基硅胶上,制备了手性固定相.正相条件下,在该固定相上直接拆分了两种三唑类杀菌剂三唑酮与戊唑醇外消旋体,并且系统地选用了多种流动相体系对样品拆分的流动相条件进行了优化,筛选出了适合三唑酮与戊唑醇拆分的流动相体系.