Structural Domain Imaging and Direct Determination of Crystallographic Orientation in Noncentrosymmetric Ca_3Ru_2O_7 Using Polarized Light Reflectance

The noncentrosymmetricity of a prototypical correlated electron system Ca₃Ru₂O₇ renders extensive interest in the possible polar metallic state,along with multiple other closely competing interactions.However,the structural domain formation in this material often complicates the study of intrinsic material properties.It is crucial to fully characterize the structural domains for unrevealing underlying physics.Here,we report the domain imaging on Ca₃Ru<...     

An efficient deterministic secure quantum communication scheme based on cluster states and identity authentication

A novel efficient deterministic secure quantum communication scheme based on four-qubit cluster states and single-photon identity authentication is proposed. In this scheme, the two authenticated users can transmit two bits of classical information per cluster state, and its efficiency of the quantum communication is 1/3, which is approximately 1.67 times that of the previous protocol presented by Wang et al [Chin. Phys. Lett. 23 (2006) 2658]. Security analysis shows the present scheme is secure against intercept-resend attack and the impersonator's attack. Furthermore, it is more economic with present-day techniques and easily processed by a one-way quantum computer.     

考尼伐坦关键中间体的合成

合成考尼伐坦关键中间体2-甲基-6-(4-甲基苯磺酰基)-1,4,5,6-四氢咪唑[4,5-d][1]苯并氮杂卓并对其工艺优化。以氨茴酸甲酯为起始原料,经保护、烃化、环合、脱羧、溴化、烃化并缩合共六步反应合成考尼伐坦关键中间体。所得的目标化合物经核磁共振氢谱、质谱确认,总收率达49.06%。该关键中间体合成方法和工艺改进后,所用原料价格便宜、反应条件温和、反应周期缩短、产率提高,更加适合于工业化生产。     

吡啶高三蝶烯的合成

2-溴-4-甲基吡啶（1）经氯代和碘代反应合成了2-溴-4-碘甲基吡啶（3）,3和蒽酮（4）反应生成10,10-二（2-溴-4-吡啶甲基）-9（10H）蒽酮（5）,5在3 MPa下与NaOCH3反应得到10,10-二（2-甲氧基-4-吡啶甲基）-9（10H）蒽酮（6）,6经硼氢化钠还原得到蒽醇（7）,7在对甲苯磺酸催化...     

电喷雾萃取电离质谱法直接检测环境水样中的邻苯二甲酸二(2-乙基己基)酯

采用电喷雾萃取电离质谱技术(Extractive electrospray ionization mass spectrometry,EESI-MS)分析水样中的有机污染物邻苯二甲酸二(2-乙基己基)酯(Di-2-ethylhexy phthalate,DEHP),系统考察了电喷雾电压、离子传输管温度、样品溶液流速及萃取剂组成对待测物信号强度的影响,优化了检测DEHP的实验条件,建立了水样中DEHP的快速质谱分析方法,并对垃圾渗滤液、城市生活污水及湖水等实际水样进行检测。结果表明,在正离子检测模式下,水样中的DEHP能够在EESI源中有效电离,生成准分子离子[M+H]~+(m/z 391.28),进行碰撞诱导解离得到二级特征碎片离子m/z 279.26,167.12,149.11。在5~1000μg/L范围内,DEHP浓度与m/z 149.11质谱峰信号强度的线性关系良好,相关系数R~2=0.9991,检出限LOD=0.21μg/L(S/N=3);水样的3个加标水平(8,80和400μg/L)的DEHP回收率为96.2%~111.2%,RSD为5.6%~11.8%。EESI-MS法检测垃圾渗滤液、城市生活污水和晏湖水中DEHP的含量分别为556.5、275.3和37.8μg/L。本方法具有无需样品预处理、分析速度快(单个样品分析时间约3 min)、操作简便、灵敏度高等优点,为邻苯二甲酸酯类物质的检测提供了一种快速质谱分析新方法。     

Attacks and Improvement of Quantum Sealed-Bid Auction with EPR Pairs

Recently, an experimentally feasible three-party quantum sealed-bid auction protocol based on EPR pairs [Z.Y. Wang, Commun. Theor. Phys. 54 （2010） 997] was proposed. However, this study points out Wang＇s protocol cannot resist some internal bidders＇ attacks, such as the Twiee-CNOT attack, the collusion attack. A malicious bidder can launch the Twice-CNOT attack to obtain the other＇s bid, or the dishonest auctioneer may collude with one bidder and help him/her win the action by changing his/her bid. For preventing against these attacks, a simple solution by using the QKD-based message encryption and a post-confirmation mechanism by adopting the hash function are proposed.     

W_(20)O_(58)(010)表面氢吸附机理的第一性原理研究

采用基于密度泛函理论的第一性原理平面波超软赝势方法,在广义梯度近似下,研究了W_(20)O_(58)晶胞、W_(20)O_(58)(010)表面结构及其氢吸附机理.计算结果表明:W_(20)O_(58)晶体理论带隙宽度为0.8 eV,为间接带隙,具有金属性.W_(20)O_(58)晶体中W—O共振较强,以共价键居多.W_(20)O_(58)(010)表面有WO终止(010)表面和O终止(010)表面,表面结构优化后使得W—O键长和W—O—W键角改变,从而实现表面弛豫.分别计算了H_2分子吸附在WO终止(001)表面和O终止(001)表面的WO-L-O_(1c),WO-V-O_(1c),WO-L-O_(2c),WO-V-O_(2c),O-L-O_(1c)和O-V-O_(1c)六种吸附构型,其中WO-L-O_(1c),WO-V-O_(1c)和WO-L-O_(2c)这三种吸附构型不稳定;而WO-V-O_(2c),O-L-O_(1c)和O-V-O_(1c)这三种吸附构型都很稳定,H_2分子都解离成两个H原子,吸附能均为负值,分别为-1.164,-1.021和-3.11 eV.WO-V-O_(2c)吸附构型的两个H原子分别吸附在O和W原子上;O-L-O_(1c)吸附构型的两个H原子,一个与O原子成键,另一个远离了表面.其中O-V-O_(1c)吸附构型最稳定,两个H原子失去电子,为O原子提供电子.分析其吸附前后的态密度,H的1s轨道电子与O的2p,2s轨道电子相互作用,均形成了一些较强的成键电子峰,两个H原子分别与O_(1c)形成化学键,最终吸附反应生成了一个H_2O分子,同时产生了一个表面氧空位.     

爆轰加载下银气溶胶源项实验研究

为研究钚气溶胶生成规律及源项分布,提出了一种密封环境下的金属气溶胶源项实验方法,利用爆炸容器及气溶胶采样器等实验设备,开展了钚替代材料银的气溶胶源项生成实验,分析了空气动力学直径小于10 μm的银气溶胶源项分布特性,并与外场扩散试验中钚气溶胶数据进行了对比。进一步采用不同炸药及加载装置,对相同银片样品进行加载实验,研究了加载峰值压力对银气溶胶源项分布的影响。研究结果表明,金属银可作为替代材料研究爆轰加载条件下钚气溶胶的源项参数,在一定实验条件下,二者归一化积累质量分布具有较高的一致性;爆轰加载产生的银气溶胶中,较小粒径气溶胶质量含量较高。气溶胶总量与加载峰值压力呈二次函数分布,当峰值压力超过某个临界值时,气溶胶总量将达到极值;此外,通过对同发次实验的3次不同采样数据进行分析,发现了较明显的气溶胶凝并和沉降现象。     

Cryptanalysis and Improvement of Quantum Private Comparison Protocol Based on Bell Entangled States

Recently, Liu et al. [Commun. Theor. Phys. 57(2012) 583] proposed a quantum private comparison protocol based on entanglement swapping of Bell states, which aims to securely compare the equality of two participants' information with the help of a semi-honest third party(TP). However, the present study points out there is a fatal loophole in Liu et al.'s protocol, and TP can make Bell-basis measurement to know all the participants' secret inputs without being detected. To fix the problem, a simple solution, which uses one-time eavesdropper checking with decoy photons instead of twice eavesdropper checking with Bell states, is demonstrated. Compared with the original protocol,it not only reduces the Bell states consumption but also simplifies the protocol steps.     

化合物分子表面积计算方法的研究

化合物的分子表面积是重要的物理化学性质参数．根据不同的应用领域及数学方法,提出了多种分子表面积算法[1-10],由此产生了“分子表面积法”,各方法的有效性在各具体应用领域都已被验证．本文将统计方法中的随机变量引入计算化合物分子表面积体系,由分子模型化技术得到化合物分子的原子坐标,不考虑化合物分子中原子的相互作用及分子间近似,直接计算分子表面积．使用该方法可以计算“净”分子表面积、“溶剂可及表面积”、甚至分子结构片段,分子结构中有交叉重叠片段及存在“空洞”的各种分子表面积,该算法及程序较简捷,适应范围广,计算结果较为满意．