利用Knoevenagel缩合反应合成聚集诱导发光型丙烯腈衍生物

传统发光材料由于聚集诱导荧光淬灭效应降低了实验教学的趣味性,开发反传统的荧光材料具有极其重要的研究意义。本文利用Knoevenagel缩合反应制备了一系列含有丙烯腈结构的荧光分子,将我国科学家引领的科学前沿——聚集诱导发光(AIE)引入实验教学,可有效增强学生的民族自豪感。通过本实验,不仅可以学习Knoevenagel缩合反应机理,掌握基础有机实验操作,而且还可提升学生学习兴趣,培养科学思维,有利于推动“有机实验”的课程思政建设。

Nonlinear dynamics of fixed-trim reentry vehicles with moving-mass roll control system

Nonlinear dynamic characteristics of a fixed-trim reentry vehicle controlled by an internal moving-mass actuator are analyzed. A traditional dynamic model develops into a five-dimensional nonlinear model using classic Euler angles and their derivatives as state variables. Based on the nonlinear motion equations, by setting the offset distance of the moving-mass as a variation parameter, the curves of the system's equilibrium points are presented by numerical methods. Then the distributions and approximate analytical solutions of the equilibrium points are obtained by simplifying the model under the condition of small intrinsic angles. The results show that the numbers and values of the equilibrium points are closely connected with the location of the moving-mass. Furthermore, the stabilities of equilibrium points are examined by the Lyapunov's first method and three groups of stable equilibrium points are obtained. Since only one group of the stable equilibrium points is desired, the angular motion of the system may be unstable or stay in an undesired lock-in state when the offset distance of the moving-mass or the attitude disturbance of the vehicle is too large. © 2016 Beijing Institute of Aerospace Information.

Quantum computation and error correction based on continuous variable cluster states

Measurement-based quantum computation with continuous variables,which realizes computation by performing measurement and feedforward of measurement results on a large scale Gaussian cluster state,provides a feasible way to implement quantum computation.Quantum error correction is an essential procedure to protect quantum information in quantum computation and quantum communication.In this review,we briefly introduce the progress of measurement-based quantum computation and quantum error correction with continuous variables based on Gaussian cluster states.We also discuss the challenges in the fault-tolerant measurement-based quantum computation with continuous variables.

Visualization of enantioselective recognition and separation of chiral acids by aggregation-induced emission chiral diamine

Enantioselective recognition and separation are the most important issues in the fields of chemistry,pharmacy,agrochemical,and food science.Here,we developed two optically active diamines showing aggregation-induced emission(AIE)that can discriminate 5 kinds of chiral acids with high enantioselectivity.Especially,a very high fluorescence intensity ratio(IL/ID)of 281 for(±)-Dibenzoyl-D/L-tartaric acid was obtained through the collection of fluorescence change after interaction with chiral AIE-active diamine.By virtue of AIE property and intermolecular acidbase interaction,enantioselective separation was facilely realized by simple filtration of the precipitates formed by chiral AIE luminogen(AIEgen)and one enantiomer in the racemic solution.The chiral HPLC data indicated that the precipitates of AIEgen/chiral acid possessed 82%L-analyte(the enantiomeric excess value was assessed to be 64%ee).Therefore,this method can serve as a simple,convenient,and low-cost tool for chiral detection and separation.

Quantum-enhanced microscopic imaging technology [Invited]

Microscopes are indispensable tools in modern biology and medicine. With the development of microscopy, the signal-tonoise ratio of microscopes is now limited by the shot noise. Recently, quantum-enhanced microscopic imaging provides a feasible approach for improving the signal-to-noise ratio since it can beat the shot-noise limit by using quantum light. In this review, we first briefly introduce quantum states applied in quantum-enhanced microscopic imaging, and then we provide an overview of the principle and progress of quantum-enhanced stimulated Raman scattering microscopy, entangled twophoton microscopy,and quantum-enhanced differential interference contrast microscopy.

Visual Detection of COVID‑19 from Materials Aspect

In the recent COVID-19 pandemic,World Health Organization emphasized that early detection is an effective strategy to reduce the spread of SARS-CoV-2 viruses.Several diagnostic methods,such as reverse transcription-polymerase chain reaction(RT-PCR)and lateral flow immunoassay(LFIA),have been applied based on the mechanism of specific recognition and binding of the probes to viruses or viral antigens.Although the remarkable progress,these methods still suffer from inadequate cellular materials or errors in the detection and sampling procedure of nasopharyngeal/oropharyngeal swab collection.Therefore,developing accurate,ultrafast,and visualized detection calls for more advanced materials and technology urgently to fight against the epidemic.In this review,we first summarize the current methodologies for SARS-CoV-2 diagnosis.Then,recent representative examples are introduced based on various output signals(e.g.,colorimetric,fluorometric,electronic,acoustic).Finally,we discuss the limitations of the methods and provide our perspectives on priorities for future test development.

Enantioselective recognition based on aggregation-induced emission

Chirality is one of the most important features of the nature.The recognition of enantiomers plays significant roles in the field of life science,pharmaceutical analysis and food chemistry.Among various recognition methods,fluorescence spectrometry has attracted much attention of researchers thanks to its high sensitivity and easy operation.Compared with traditional fluorescent probes,chiral molecules with aggregation-induced emission(AIE)have drawn increasing interests due to their huge potential in high-efficiency chemo/biosensors and solid emitters.Chiral AIE luminogens(AIEgens)can not only discriminate two enantiomers with excellent enantioselectivity,but also show general applicability for many chiral analytes,such as chiral acids,amino acids,amines,alcohols.In this review,we mainly summarized the recent development of chiral probes with AIE properties,including chiral tetraphenylethylene(TPE)derivatives,α-cyanostilbene derivatives,Schiff base derivatives and other AIEgens.Their synthetic routes,recognition capabilities and possible working mechanisms were well discussed.It is envisioned that the present review can give some significant guidance for design and synthesis of chiral AIEgens with good enantioselectivity and inspire more readers to join the research of chiral AIE.

基于低管秩张量分解的互质阵列自适应波束成形算法

互质阵列因其大阵列孔径和高自由度特性在波束成形领域受到广泛关注.为了充分利用该特性,近年来学者们提出了基于孔洞填充的算法,有效提高了互质阵列波束成形的性能.然而,这些算法存在计算量大、噪声鲁棒性弱等缺点,难以适应复杂多变的实际环境.为此,本文利用张量的多维结构在参数估计上的性能优势,提出了一种基于低管秩张量分解的互质阵列自适应波束成形算法.首先将互质阵列的多采样虚拟信号矩阵重排为张量形式,利用其低管秩特性补全缺失的互相关信息;然后从补全后的张量数据中提取信号参数,并与目标先验进行匹配,最终得到波束成形权矢量.本算法分别利用ADMM和Tucker分解提高了张量补全和分解的运算效率;所设计的目标匹配方案也有效控制了算法误差.仿真结果展示了本算法在性能和计算复杂度相对于现有方法的优势,尤其是在低信噪比和少采样数的情况下.

Applying Gaussian quantum discord to quantum key distribution

In this paper, we theoretically prove that the Gaussian quantum discord state of optical field can be used to complete continuous variable(CV) quantum key distribution(QKD). The calculation shows that secret key can be distilled with a Gaussian quantum discord state against entangling cloner attack. Secret key rate is increased with the increasing of quantum discord for CV QKD with the Gaussian quantum discord state. Although the calculated results point out that secret key rate using the Gaussian quantum discord state is lower than that using squeezed state and coherent state at the same energy level, we demonstrate that the Gaussian quantum discord, which only involving quantum correlation without the existence of entanglement, may provide a new resource for realizing CV QKD.

Experimental test of error-disturbance uncertainty relation with continuous variables

The uncertainty relation is one of the fundamental principles in quantum mechanics and plays an important role in quantum information science. We experimentally test the error-disturbance uncertainty relation(EDR) with continuous variables for Gaussian states. Two incompatible continuous-variable observables, amplitude and phase quadratures of an optical mode, are measured simultaneously using a heterodyne measurement system.The EDR values with continuous variables for coherent, squeezed, and thermal states are verified experimentally.Our experimental results demonstrate that Heisenberg’s EDR with continuous variables is violated, while Ozawa’s and Branciard’s EDRs with continuous variables are validated.

Deterministic distribution of orbital angular momentum multiplexed continuous-variable entanglement and quantum steering

Orbital angular momentum(OAM)multiplexing provides an efficient method to improve data-carrying capacity in various quantum communication protocols.It is a precondition to distribute OAM multiplexed quantum resources in quantum channels for implementing quantum communication.However,quantum steering of OAM multiplexed optical fields and the effect of channel noise on OAM multiplexed quantum resources remain unclear.Here,we generate OAM multiplexed continuous-variable(CV)entangled states and distribute them in lossy or noisy channels.We show that the decoherence property of entanglement and quantum steering of the OAM multiplexed states carrying topological charges l=1 and l=2 are the same as that of the Gaussian mode with l=0 in lossy and noisy channels.The sudden death of entanglement and quantum steering of high-order OAM multiplexed states is observed in the presence of excess noise.Our results demonstrate the feasibility to realize high data-carrying capacity quantum information processing by utilizing OAM multiplexed CV entangled states.

Quantifying quantum coherence of optical cat states

The optical cat state plays an essential role in quantum computation and quantum metrology. Here, we experimentally quantify quantum coherence of an optical cat state by means of relative entropy and the l1 norm of coherence in a Fock basis based on the prepared optical cat state at the rubidium D1 line. By transmitting the optical cat state through a lossy channel, we also demonstrate the robustness of quantum coherence of the optical cat state in the presence of loss, which is different from the decoherence properties of fidelity and Wigner function negativity of the optical cat state. Our results confirm that quantum coherence of optical cat states is robust against loss and pave the way for the application of optical cat states.

Experimental demonstration of robustness of Gaussian quantum coherence

Besides quantum entanglement and steering,quantum coherence has also been identified as a useful quantum resource in quantum information. It is important to investigate the evolution of quantum coherence in practical quantum channels. In this paper,we experimentally quantify the quantum coherence of a squeezed state and a Gaussian Einstein–Podolsky–Rosen (EPR) entangled state transmitted in Gaussian thermal noise channel. By reconstructing the covariance matrix of the transmitted states,quantum coherence of these Gaussian states is quantified by calculating the relative entropy. We show that quantum coherence of the squeezed state and the Gaussian EPR entangled state is robust against loss and noise in a quantum channel,which is different from the properties of squeezing and Gaussian entanglement. Our experimental results pave the way for application of Gaussian quantum coherence in lossy and noisy environments.