Eu2+掺杂MgY2Al3Si2O11N青光荧光粉的制备和发光性能

采用高温固相法合成了一系列Eu²⁺掺杂的MgY²Al³Si²O¹¹N(MYASON)青光荧光粉。详细探讨了不同制备方法对荧光粉的物相结构和发光强度的影响,利用X射线衍射精修和X射线光电子能谱实验证明Si⁴⁺-N^3-离子对成功掺入石榴石晶格中。通过荧光光谱、寿命衰减曲线和变温光谱研究了发光性能,研究结果表明,用365 nm紫外光激发MYASON∶Eu²⁺荧光粉时,在青光区域呈现不对称宽带发射,峰值为490 nm,可以为紫外芯片激发的白光发光二极管有效提供青光成分。     

Authenticable Quantum Scheme for Secret Sharing Based on Local Distinguishability

The main defects of the existing quantum secret sharing schemes are as follows: (1) The identity of the secret sender cannot be confirmed. Receivers of shared secret information may be vulnerable to Trojan attacks; (2) If a malicious attacker Eve impersonates the identity of the receiver, she can finally obtain all the information of the secret that Alice shared; (3) In the process of secret recovery, it is necessary to transmit qubits among all participants involved in secret recovery. Sometimes, the same particle needs to be operated on by all participants to achieve secret sharing, which increases the possibility of eavesdropping and also increases the probability of errors. In this work, we proposed a quantum secret sharing scheme with authentication, the receiver performs corresponding operations on qubits of Greenberger-Horne-Zeilinger(GHZ) state based on the key string calculated by the shared identity number and random Error Correction Code(ECC), the secret sender can calculate the corresponding measurement basis(MB) through the information she has, and then inform the measurement party. This process realizes the mutual authentication between the sender and the receiver. It can protect against identity impersonation attacks, through the ECC verification, it also can resist intercept-resend attacks.

     

十字环型左手材料单元结构设计与仿真

提出了一种新型十字环型左手材料结构单元.该结构只需在介质板单侧蚀刻, 即可在二维方向上产生等效负介电常数和等效负磁导率.通过理论分析, 提出场-路结合的等效源分析法以计算等效介电常数、磁导率, 并据此对十字环型结构单元的左手特性激发机理进行了论证. 后采用Nicolson-Ross-Weir 等效参数法提取了十字环型单元阵列的相对介电常数和相对磁导率, 并通过棱镜实验对材料的负折射特性进行了验证.实验表明, 该左手材料在6.8-6.9 GHz频段具有二维入射左手特性. 此种左手材料制作工艺相对简单, 为左手材料在微波器件领域的应用提供了一种较为实用的设计方案.     

聚丙烯酰胺水溶液的流变性质

粘性指进现象;聚丙烯酰胺水溶液的流变性质     

Spectrophotometric determination of a thiobarbituric acid-reactive substance in human hair.

A simple and sensitive spectrophotometric method for the determination of a thiobarbituric acid-reactive substance (TBARS) in human hair has been developed. The proposed method is based on the formation of a red-colored product by the reaction of products of lipid peroxidation with thiobarbituric acid in an acidic medium. The absorbance of the resulting red product was measured at 534 nm. The linear dynamic range was between 1.0 and 20 micromol/L. The recoveries were 98.3-105.0%, and the relative standard deviations (RSD) were 0.32-1.24, respectively. TBARS in digested hair sample was stable for 3 days at room temperature. It was found that, using this method, the hair TBARS concentration in smokers (0.116 +/- 0.030 micromol/g, n = 30) was significantly higher than that in non-smokers (0.096 +/- 0.015 micromol/g, n = 30) (p < 0.05).     

ZnS纳米球的水热法制备及其光催化性能研究

在表面活性剂十六烷基三甲基溴化铵(CTAB)的辅助下,以乙酸锌为锌源,硫脲(NH2)2CS为硫源,使用水热法通过改变反应时间,成功制备了不同粒径的ZnS球状颗粒。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、X-射线能谱,高分辨透射电子显微镜(HRTEM))、紫外可见分光光谱和光致发光谱(PL)等测试手段对样品的晶体结构、形貌、光学性质进行了分析。通过对不同粒径的ZnS纳米颗粒对亚甲基蓝的光催化降解的催化活性进行了评估。实验结果表明:在表面活性剂CTAB的作用下,随着反应时间的增加,生成的ZnS晶核生长成纳米颗粒,然后ZnS纳米颗粒将进一步发生团聚从而形成平均粒径超过500nm的ZnS纳米球,但制备的ZnS产物的晶体结构均为立方纤锌矿结构。随着ZnS粒径的增加,样品的紫外吸收峰从418nm逐渐蓝移到362nm,而PL发射峰位的峰强随着粒径的增大而增强。光催化结果显示,反应12h制备的ZnS纳米球的光催化性能最佳。     

Tribological characteristics of ZnO nanowires investigated by atomic force microscope

Zinc oxide (ZnO) nanowires have attracted great interest in nanodevices. In this work, the tribological characteristics of vertically grown ZnO nanowires obtained by metalorganic chemical vapor deposition were investigated by using an atomic force microscope (AFM). The ZnO nanowires were slid against flattened silicon and diamond-coated AFM probes under 50–150 nN normal force while monitoring the frictional force. The wear of the ZnO nanowires was observed by a scanning electron microscope and quantified based on Archard’s wear law. Also, the wear debris accumulated on the silicon probe was analyzed by using a transmission electron microscope (TEM). The results showed that the wear of ZnO nanowires slid against the silicon probe was extremely small. However, when the ZnO nanowires were slid against the diamond-coated probe, the wear coefficients ranged from 0.006 to 0.162, which correspond to the range of severe wear at the macroscale. It was also shown that the friction coefficient decreased from 0.30 to 0.25 as the sliding cycles increased. From TEM observation, it was found that the ZnO wear debris was mainly amorphous in structure. Also, crystalline ZnO nanoparticles were observed among the wear debris. PACS  07.79.Lh; 46.55.+d; 81.07.Bc     

三维微纳米制造技术在癌症生物物理研究中的应用

癌症致命的主要原因是癌细胞在临床上的转移性. 癌细胞的侵袭和转移是一个非常复杂的三维过程, 但现有的癌症研究在活体上有诸多观测和操作上的困难. 而体外实验又通常在培养皿中进行, 其二维的生长环境已完全不能满足对癌细胞空间转移性的深入研究, 故在活体外构建出癌细胞侵袭和转移的三维物理模型具有十分重要的意义. 然而如何在体外尽可能真实地模拟体内癌细胞的生长微环境一直是困扰科学家的难题. 本文系统介绍了三维微纳米制造的几种主流技术, 探讨了它们在癌症生物物理研究中的应用和发展. 在此基础上为了在未来实现对体外三维模型的制造、观测和精确操作, 文章还创新性地提出了一种结合紫外线固化生物型水凝胶的三维成型技术、光片三维成像技术以及微纳米探针控制技术的一体化研究平台. 这些先进的技术和理念, 势必会逐步升级现有传统的癌症研究手段, 为未来理解和治疗癌症揭开全新的篇章.     

荷电液滴捕集细颗粒物的数值模拟研究

对固定荷电液滴吸附细颗粒物进行了数值模拟计算。采用微漏电模型计算电场分布和作用在液滴上的电场力。利用VOF模型追踪液滴自由界面,考虑自由界面流体体积分数过渡引起的物性参数变化。通过求解牛顿方程计算固体细颗粒物的运动轨迹。计算模拟了细颗粒物在库仑力、电场力、流体黏阻以及重力的作用下脱离基底被荷电液滴捕集的全过程,分析了不同电场强度、颗粒粒径以及液滴粒径等因素对吸附效率的影响。计算结果与实验结果吻合较好。     

基于多尺度均值漂移的高分辨率遥感影像快速分割方法

均值漂移算法是一种特征空间分析方法,广泛应用于自然场景影像和医学影像分割中.但算法较高的计算复杂度成为其在具有海量特性的遥感影像中应用的瓶颈.文章将均值漂移算法拓展到小波域,提出了一种小波域均值漂移快速分割算法.多光谱遥感影像和仿真影像的实验表明:在获得相当的分割结果的前提下,相比单尺度均值漂移算法,提出的分割算法能够...