时间域方法分析镍卟啉的共振拉曼强度与S2激发态结构

研究了入射光波长与S0→S2跃迁共振的情形下,卟啉镍合物（NiP)的振动拉曼光谱。用时间域方法计算了NiP的共振拉曼强度和吸收光谱。结果表明,相对于基态,S2态NiP的分子构型沿着v8和v2简正坐标有较大的位移。这些简正坐标主要涉及卟啉环的CαCm键和CβCβ键伸缩运动,以及CαCmCα变角运动。与基态相比,S2态的CβCβ、CαCm和CαN键分别增大0．27、0．14、0．07pm,而CαCβ键则减小0．20pm,与前人的赝势分子轨道计算（SPMO）结果相近。还从RR强度角度讨论了S2态的Jahn-Teller畸变。     

Scalable Quantum Controlled Gates on Single-Photon Polarization Qubits Assisted by Nitrogen-Vacancy Centers Inside Single-Sided Optical Cavities

International Journal of Theoretical Physics - Quantum logic gates are the foundation of circuit-based quantum computation and quantum simulation. Multi-qubit quantum controlled gates are of vital...     

Common (π,π) Band Folding and Surface Reconstruction in Fe As-Based Superconductors

High resolution angle-resolved photoemission spectroscopy(ARPES) measurements are carried out on CaKFe_4 As_4,KCa_2 Fe_4 As_4 F_2 and(Ba_(0.6)K_(0.4))Fe_2 As_2 superconductors.Clear evidence of band folding between the Brillouin zone center and corners with a(π,π) wave vector has been found from the measured Fermi surface and band structures in all the three kinds of superconductors.A dominant ~(1/2)×~(1/2) surface reconstruction is observed on the cleaved surface of CaKFe_4As_4 by scanning tunneling microscopy(STM) measurements.We propose that the commonly observed ~(1/2)×~(1/2) reconstruction in the FeAs-based superconductors provides a general scenario to understand the origin of the(π,π) band folding.Our observations provide new insights in understanding the electronic structure and superconductivity mechanism in iron-based superconductors.     

Brain-like synaptic memristor based on lithium-doped silicate for neuromorphic computing

Artificial synapse is one of the potential electronics for constructing neural network hardware. In this work, Pt/LiSiO_x/TiN analog artificial synapse memristor is designed and investigated. With the increase of compliance current (C. C.) under 0.6 mA, 1 mA, and 3 mA, the current in the high resistance state (HRS) presents an increasing variation, which indicates lithium ions participates in the operation process for Pt/LiSiO_x/TiN memristor. Moreover, depending on the movement of lithium ions in the functional layer, the memristor illustrates excellent conduction modulation property, so the long-term potentiation (LTP) or depression (LTD) and paired-pulse facilitation (PPF) synaptic functions are successfully achieved. The neural network simulation for pattern recognition is proposed with the recognition accuracy of 91.4%. These findings suggest the potential application of the LiSiO_x memristor in the neuromorphic computing.     

具有抗多种活性氧酶功能的金属卟啉的研究—钌卟啉仿酶活性测试

二价金属钌卟啉[Ru^Ⅱ(4-Cl-TPP)(CO)](1),[Ru^Ⅱ(4-MeO-TPP)(CO)](2),[Ru^Ⅱ(C,4,5-MeO-TPP)(CO)](3)和六价金属钌卟啉[Ru^Ⅵ（4Cl-TPP)(O)2](4),[Ru^Ⅵ(4-MeO-TPP)(O)2](5),[Ru^Ⅵ(3,4,5-MeO-TPP)(O)2](6)被合成,配合物1－6作为超氧化物歧化酶（SOD）和过氧化氢酶（CAT）功能模拟酶被测试,核黄素－蛋胺酸光照法证实,钌啉啉在不同浓度范围内有催化歧化O^.-2的作用,分光光度法证实能催化H2O2分解,用小鼠肝匀浆法测度试结果表明：金属钌啉具有良好的抗脂质过氧化作用,提出了金属钌卟啉在催化歧化超氧阴离子自由基（O^.-2)和催化分解过氧化氢（H2O2）协同过程中的可能机理,并讨论了卟啉环上不同取代基对催化活性的影响。     

nc-Ge/SiN_x多层膜的光致发光特性

通过将a-Ge∶H/a-SiN_x多层膜进行氧化,制备了nc-Ge/SiN_x多层膜。观察到了室温下的强烈可见光发射,发光波长为500nm。通过分析,排除了与量子限制效应有关的光发射机制,也排除了与Si和N相关的缺陷产生的复合机制,认为该发光源于氧化后的a-SiN_x介质层中带尾态之间的辐射复合,最有效的激发能量约为介质层的带隙。     

Graphene-based passively Q-switched Nd:KLu(WO4)2 eye-safe laser operating at 1,425 nm

With graphene as saturable absorber, an Nd:KLu(WO₄)₂ eye-safe laser operating at 1,425 nm is demonstrated. To the best of our knowledge, this is the first demonstration that an Nd:KLu(WO₄)₂ laser operates at the eye-safe 1.4-μm region. A maximum total average output power of 170 mW is obtained under the pump power of 9.6 W, corresponding to an optical–optical efficiency of 1.77 %. The minimum pulse width and the highest pulse repetition rate are 153 ns and 97 kHz, respectively. Also the characteristics of the graphene used as saturable absorber for a 1.4-μm laser were studied for the first time.     

Approximate time-optimal control of quantum ensembles based on sampling and learning

For a general quantum ensemble with Hamiltonian fluctuations, this paper proposes a sampling-based two-stage approximate time-optimal control algorithm with momentum terms and achieves a high-fidelity state transition of all member systems to a common target state within an approximate minimum time. The fidelity and the control time are respectively optimized in the two stages. In particular, the introduction of momentum terms greatly improves the convergence rate of the algorithm. Simulation experiments on a two-level quantum ensemble verify the effectiveness of the proposed algorithm.     

Comparison of <Emphasis Type="Italic">c</Emphasis>-Nd:YVO<Subscript>4</Subscript>/YVO<Subscript>4</Subscript> raman lasers and <Emphasis Type="Italic">c</Emphasis>-Nd:YVO<Superscript>4</Superscript> self-Raman lasers

Raman lasers based on c-Nd:YVO₄ crystals can generate 1178 nm Stokes line, which can be frequency-doubled to realize 589 nm sodium lasers. We make comparative experimental studies of c-Nd:YVO₄/YVO₄ Raman lasers and c-Nd:YVO₄ self-Raman lasers. About these two kinds of lasers, the output characteristics of power, center wavelength and beam quality are measured and compared.     

Optical oxygen sensing materials based on a novel dirhenium(I) complex assembled in mesoporous silica

A new dirhenium(I) complex fac-[{Re(CO)₃(4,7-dinonadecyl-1,10-phenanthro -line)}₂ (4,4′-bipyridyl)] (trifluoromethanesulfonate)₂ (denoted as D-Re(I) ) is assembled in MCM-41 and SBA-15 type mesoporous silica support. The emission peaks of D-Re(I) in D-Re(I)/MCM-41 and D-Re(I)/SBA-15 are observed at 522 and 517 nm, respectively. Their long excited lifetimes, which are of the order of microseconds, indicate the presence of phosphorescence emission arising from the metal to ligand charge-transfer (MLCT) transition. The luminescence intensities of D-Re(I)/MCM-41 and D-Re(I)/SBA-15 decrease remarkably with increase in the oxygen concentration, meaning that they can be used as optical oxygen sensing materials based on luminescence quenching. The ratios I₀/I₁₀₀ of D-Re(I)/MCM-41 and D-Re(I)/SBA-15 are estimated to be 5.6 and 20.1, respectively. The obtained Stern-Volmer oxygen quenching plots of the mesoporous sensing materials could be fitted well to the two-site Demas model and Lehrer model.