Liquid Nuclear Magnetic Resonance Implementation of Quantum Computation in Subspace

Based on the logical labelling method, we prepare an effective pure state in a subsystem of a three spin system via liquid nuclear magnetic resonance technique. Then with this subspace effective pure state we implement the Deutsch-Jozsa algorithm. The tomography for the subspace effective pure state and the corresponding spectrum of the output for the Deutsch-Jozsa algorithm agree with theoretical predictions, which shows that we have successfully implemented the Deutsch-Jozsa algorithm in a subsystem of a nuclear spin system and demonstrated a subspace quantum computation.     

Theoretical Investigation on Excitation,Ionization and Capture in H（1s, 2s） ＋ H（1s, 2s） Collisions

Cross sections of electron-loss in H（1s）＋ H（1s） collisions and total collisional destruction of H（2s） in H（1s） 4- H（2s） collisions are calculatted by four-body classical-trajectory Monte Caylo （CTMC） method and compared with previous theoretical and experimental data over the energy range of 4-100 keV. For the former a good agreement is obtained within different four-body CTMC calculations, and for the incident energy Ep 〉 10 keV, comparison with the experimental data shows a better agreement than the results calculated by the impact parameter approx- imation. For the latter, our theory predicts the correct experimental behaviour, and the discrepancies between our results and experimental ones are less than 30%. Based on the successive comparison with experiments, the cross sections for excitation to H（2p）, single- and double-ionization and H- formation in H（2s）＋H（2s） collisions are calculated in the energy range of 4-100 keV for the first time, and compared with those in H（1s）＋H（1s） and H（1s）＋U（2s） collisions.     

摄动有限体积法重构近似高精度的意义

研讨有限体积(FV)方法重构近似高精度的作用问题.FV方法中积分近似采用中点规则为二阶精度时,重构近似高精度(精度高于二阶)的意义和作用是一个有争议的问题.利用数值摄动技术[1,2]构造了标量输运方程的积分近似为二阶精度、重构近似为任意阶精度的迎风型和中心型摄动有限体积(PFV)格式.迎风PFV格式无条件满足对流有界准则(CBC),中心型PFV格式为正型格式,两者均不会产生数值振荡解.利用PFV格式求解模型方程的数值结果表明:与一阶迎风和二阶中心格式相比,PFV格式精度高、对解的间断分辨率高、稳定性好、雷诺数的适用范围大,数值地"证实"重构近似高精度和PFV格式的实际意义和好处.     

拓扑缺陷的不同分布对单壁碳纳米管电学性能的影响

在紧束缚近似基础上,利用扩展的Su-Schriffer-Heeger(SSH)模型,在实空间研究了在完整的"zigzag"碳纳米管中分别引入5/7,5/6/7,5/6/6/7拓扑缺陷所构成的(9,0)-(8,0),(9,0)-(7,0)和(9,0)-(6,0)三种异质结的电学性能.通过研究表明:这些拓扑缺陷不仅改变碳管的直径,而且支配费米能级附近的电学行为.并计算了(9,0)-(8,0),(9,0)-(7,0)和(9,0)-(6,0)系统的电子态密度,对这3种异质结的能带结构和电子态密度进行了比较.结果表明:五边形和七边形在碳管中分布的不同对碳管电学性能的影响明显不同.因此,可以研制出基于这些异质结的不同的电子器件基元.     

基于响应面模型的高超声速低温喷管优化

 建立了高超声速低温(HYLTE)喷管的响应面模型,样本点设计矩阵采用正交试验设计法构造,样本数据通过3维粘性NS方程计算喷管光腔耦合段的多组分混合流场获得。基于HYLTE喷管响应面模型,对喷管进行了多目标优化,定义了综合性能参数,优化后喷管混合性能显著改善,综合性能明显提高。计算表明,基于响应面模型的优化策略,能够满足喷管优化对计算精度和计算量的要求。运用多学科设计优化软件框架iSIGHT作为建模和优化的辅助工具,提高了优化设计的实现效率。     

CdS/PAMAM与氨基酸作用研究及其在潜在指印显现中的应用

提出了以硫化镉/聚酰胺-胺树形分子(CdS/PAMAM)纳米复合材料显现潜在指印的新方法。傅里叶变换光谱研究了PAMAM G4.5外部酯端基与氨基酸中胺基之间的胺解反应,选用相对峰高比H_{1 267/1 735}来监测不同条件下的反应进程,并发现温度对于胺解反应的影响很大,90 ℃时胺解反应可在4h内显著进行,120 ℃时胺解反应速率在3 h后发生递减。将CdS/PAMAM作为指印显现试剂,在同等条件下与现有常规指印显现液对比,发现前者的荧光强度约为后者的65倍,荧光性能优势明显。确定使用加热压显法显现不同客体表面潜在指印的条件为120 ℃下反应0.5～3 h。使用优化后的条件对多种载体表面潜在指印进行显现,可以获得理想的显现效果。该显现方法具有简便、快速、灵敏、安全、经济等特点。     

M+AsF6-(M=Li,Na,K,Rb和Cs)离子对的结构和振动光谱

利用abinitio计算方法研究了AsF6-阴离子和M AsF6-(M =Li ,Na ,K ,Rb 和Cs )直接接触离子对的结构和光谱行为。结果表明,具有C3V结构三齿相互作用的M AsF6-最稳定,二齿配位的结构只有在特定条件下才可能稳定存在。当形成离子对后,阳离子与AsF6-的相互作用将改变AsF6-的结构,这其中Li 的影响最大。另外,AsF6-光谱的变化可用来指认溶液中离子的缔合和离子对的种类。     

Spin Parity Effect on Magnetic Relaxation by Quantum Tunneling in Nanomagnets

Spin parity effect on magnetic relaxation by quantum tunneling in the biaxial spin model is studied by taking into account the transverse local stray field. It is shown that the square root time dependence in the even resonance occurs in the presence of a distribution of transverse anisotropic parameters, while the odd resonance always shows exponential relaxation. Magnetic relaxation under a sweeping field is also studied. The variation of the relaxation curve with the increasing distribution width of the local stray field for even resonance is qualitatively different from that of the odd resonance. The theoretical result on even resonance is in agreement with experimental results on Fe8 system, while the prediction for odd resonance awaits the experimental verification.