负梯度声速下特征声线与传播时间快速求解方法

求解特征声线最直接的方法是采用"扫描-插值-迭代"的声线跟踪法,过程较复杂,计算速度较慢。将负梯度声速环境下特征声线的起始掠射角表示为声速、海水深度、声源与接收点相对位置的方程,通过采用量子粒子群算法求解方程直接获得掠射角,进而确定特征声线和传播时间。与声线跟踪法相比,所提出的方法由于不存在数值累计误差和角度插值误差,因此精度更高,另外速度也更快,适合浅海负梯度环境下特征声线与传播时间的快速求解。     

Atom probe tomography of nanoscale architectures in functional materials for electronic and photonic applications

Microscopy has played a central role in the advancement of nanoscience and nanotechnology by enabling the direct visualization of nanoscale structure, leading to predictive models of novel physical behaviors. Electronic and photonic device technologies, whose features and performance are often improved through miniaturization, have particularly benefited from new capabilities in the characterization of material structure and composition. This paper reviews recent applications of atom probe tomography to semiconducting materials with nanoscale architectures that are designed to impart novel properties and device functionality by virtue of their shape and size. A review is necessary because rapid advances in atom probe instrumentation and analysis in the last decade have greatly expanded the utility of atom probe tomography to address scientific questions and technical questions in this area. The paper is organized in terms of the surface topologies of nanoscale architectures. We begin with nominally planar interfaces including thin film heterostructures and superlattices with open surfaces. Distinctive capabilities in the analysis of interfaces are introduced, as are challenges arising from measurement artifacts. We then discuss nanowires and nanowire heterostructures with surfaces that are closed along one dimension, for which atom probe tomography has provided unique and important understandings on the doping processes. Finally, we consider nanocrystals and quantum dots with completely closed surfaces. Along the way, current challenges and opportunities for atom probe tomography are highlighted, and the reader is directed to complementary reviews of more technical aspects of atom probe analysis.     

量子计算智能导论教学探索

随着智能信息处理技术的飞速发展,越来越多的学生对量子计算智能导论这门课产生了浓厚的兴趣。我们结合教学实践,将该门课程的教学内容划分为理论型和实践型,注重理论与实际应用相结合,以具体实例引导教学,从而加深学生对理论的理解,进而培养学生的实践能力和科研兴趣。本文介绍了这种教学方法。     

基于高维纠缠交换的无酉操作确定性安全量子通信

在分析高维Bell态纠缠交换基本性质的基础上,提出不需要任何酉操作、具有通用性和一般性的高维确定性安全量子通信方案.利用高维Bell测量的结果,发送方和接收方分别进行模加、减运算即可编码、解码信息.构造了两组互补的基,并根据其互补性质,提出了检测高维量子信道是否安全的方法.详细分析了几种常用攻击策略,并计算了这些攻击所引起的错误率,进而推导出通信双方需设定的错误率阈值的上界.     

Multi-party covert communication with steganography and quantum secret sharing

In this paper, we address the “multi-party covert communication”, a stronger notion of security than standard secure multi-party communication. Multi-party covert communication guarantees that the process of it cannot be observed. We propose a scheme for steganographic communication based on a channel hidden within quantum secret sharing (QSS). According to our knowledge nobody has ever raised the scheme, providing us the motivation for this work. To an outside observer, participants will engage in a typical instance of QSS, just like the others. But when the session is over, covert multi-party communication has already been done. Further analysis shows that the amount of hidden information one can acquire is 0, even if either an outside observer guesses the covert communication is carrying on or a dishonest participant is eavesdropping.     

量子密码在无线局域网中的安全研究

本文通过对量子密码BB84协议及IEEE802.11i认证协议的分析与讨论,深入研究了802.11i密钥管理机制中的4次握手,利用量子密码安全的优势与IEEE802.11i无线网络相结合,提出量子握手,为无线网络中数据的通信安全提供保障。     

Ring signature scheme based on multivariate public key cryptosystems

The ring signature scheme is an important cryptographic primitive that enables a user to sign a message on behalf of a group in authentic and anonymous way, i.e. the recipient of the message is convinced that the message is valid and it comes from one of the group members, but does not know who the actual signer is. Currently, all the existing ring signatures are based on traditional cryptosystems. However, the rapid advances in the field of quantum computing indicate a growing threat to traditional cryptosystems. Multivariate public key cryptosystems (MPKCs) is one of the promising alternatives which may resist future quantum computing attacks. In this work, we propose a novel ring signature scheme based on multivariate polynomials with the security model for the first time. Our ring signature scheme has a great advantage in efficiency compared to many existing ring signature schemes, and currently it seems to be immune to quantum computing attacks.     

A photoluminescence-based quantum semiconductor biosensor for rapid in situ detection of Escherichia coli

This work describes a novel method of detecting Escherichia coli using photoluminescence (PL) emission from III–V quantum semiconductor (QS) devices functionalized with two different antibody-based architectures. The first approach employed self-assembled monolayers of biotinylated polyethylene glycol thiols to immobilize biotinylated antibody via neutravidin. In the second approach, we used QS microstructures coated with a thin layer of Si₃N₄ allowing direct functionalization with E. coli antibodies through hydrofluoric acid etching and glutaraldehyde-based reticulation. Atomic force, optical and fluorescence microscopy measurements were used to assess the immobilization process. Depending on the biosensing architecture, density of the immobilized bacteria was observed in the range of 0.5–0.7 bacteria/100 μm². The detection of E. coli at 10⁴ CFU/ml was achieved within less than 120 min of the bacteria exposure. It is expected that an even better sensitivity threshold could be achieved following further optimization of the method.     

Synthesis of quantum size ZnO crystals and their gas sensing properties for NO2

Quantum size ZnO crystals have been synthesized successfully by a room temperature sol-gel process. Oleic acid (OA) has been used as capping agent to control the particle size of ZnO. The crystal structure and size of the ZnO are characterized by the X-ray diffraction (XRD) and transmission electron microscope (TEM). The XRD results show the as-synthesized ZnO has hexagonal wurtzite structure and the average crystallite size is 5.7 nm which is little less than TEM result. It is testified by photoluminescence (PL) and Raman spectra that the quantum size ZnO keeps the crystal structure of the bulk ZnO and possesses more surface defects. The quantum size ZnO has the highest response of 280 to NO₂ and the highest selectivity of 31 and 49 corresponding to CO and CH₄ at operating temperature of 290 °C. The effect of calcination temperatures on sensing property and transient response of the ZnO sensor are also investigated.     

On a class of languages recognizable by probabilistic reversible decide-and-halt automata

We analyze the properties of probabilistic reversible decide-and-halt automata (DH-PRA) and show that there is a strong relationship between DH-PRA and 1-way quantum automata. We show that a general class of regular languages is not recognizable by DH-PRA by proving that two “forbidden” constructions in minimal deterministic automata correspond to languages not recognizable by DH-PRA. The shown class is identical to a class known to be not recognizable by 1-way quantum automata. We also prove that the class of languages recognizable by DH-PRA is not closed under union and other non-trivial Boolean operations.