A centrosymmetric chaos

Symmetry plays an important part in the research of the dynamical behavior of nonlinear system. It is proved in this paper that, for a class of centrosymmetric systems with parametric excitation, chaos behaves in centrosymmetric manner, which implies that chaos need not to be an unsymmetric dynamical state. The project supported by National Natural Science Foundation of China     

Patterned polyelectrolyte multilayer: surface modification for enhancing selective adsorption

This paper describes the use of surface chemical modification to enhance the difference of the surface charge on a patterned polyelectrolyte multilayer, which can be used for selectively adsorbing functional materials. We fabricated a patterned multilayer by combining the layer-by-layer self-assembly technique and photolithography and taking advantage of the different solubility of polyelectrolyte multilayers of diazo resins (DAR)/poly(acrylic acid) before and after UV irradiation. This patterned surface can be used as a matrix for selective adsorption of small molecular dyes, such as Methylene Blue. However the difference in surface charge on the patterned surface was not enough when we used it to selectively adsorb polystyrene (PS) nanoparticles using electrostatic force as the driving force. Therefore, we modified the patterned surface by interfacial chemistry. After modification, the patterned polyelectrolyte multilayer can be used as a good matrix for selective adsorption of PS nanoparticles with both positive and negative charges.     

γ射线辐照对掺Yb光纤材料性能的影响

采用改进的化学气相沉积法制备掺Yb石英光纤预制棒,以该预制棒制备了尺寸为10/130μm的双包层掺Yb光纤,将这些光纤分成若干组,在不同剂量的60Coγ辐射源下辐照,测试了光纤在辐射前后的吸收谱和激光性能以及光纤预制棒切片辐照后的吸收.实验结果表明:光纤中已存在的色心缺陷(如氧空位(II))和辐照引起的色心缺陷(如E’心、过氧基以及Yb2+离子)等因素的叠加作用可能导致辐照后的光纤在可见光区域的吸收显著增大;与辐照前相比,辐照后光纤的斜率效率、光-光效率显著下降,剂量越大激光性能下降得越厉害;基于Power-Law定理拟合了光纤辐致损耗与所受剂量的关系曲线,定量分析了不同剂量辐照后光纤激光性能下降的原因.研究结果将为进一步发展抗辐照光纤提供理论和实验依据.     

烟嘧磺隆分子印迹聚合物表面等离子共振传感器的制备与分析应用

利用分子印迹技术与表面等离子共振光谱联用,建立了对磺酰脲类除草剂烟嘧磺隆的检测方法.实验过程中,探讨了pH值对分子印迹膜吸附目标化合物特性的影响,并在最佳pH下对其吸附和选择性能进行了评价.与非印迹聚合物相比,烟嘧磺隆印迹聚合物对烟嘧磺隆吸附效率比烟嘧磺隆类似物高.该方法的线性范围为5.0×10-12～25×10-12 mol/L.烟嘧磺隆和分子印迹聚合物之间的结合常数为1.6×1010 L/mol,吉布斯自由能变化值为-58.148 kJ/mol.研究结果表明该方法具有简单、快速、灵敏度高、重复性好等特点,适用于自来水和土壤中磺酰脲类除草剂烟嘧磺隆的测定,基于信噪比为3时,自来水和土壤的检出限分别为5.62×10-14和1.01×10-13mol/L,平均回收率分别为85.6%和76.6%,相对标准偏差分别为1.78%和3.21%.     

Ionic liquids as novel guests for cucurbit[6]uril in neutral water

Cucurbit[6]uril was dissolved through encapsulation of an imidazolium-based ionic liquid guest in a pure water environment and the dissolution ability could be tuned by augmenting the imidazolium structure.     

基于单光子的单向量子安全通信协议

提出了基于单光子的单向量子安全通信方案.发送方在对信息序列进行编码操作之前首先将其和随机序列进行异或操作并插入校验序列.接收方收到光子后对其进行延迟，此后发送方公布编码基从而使接收方在正确的基下进行测量.接着双方通过校验序列判断信道的安全性，如果信道安全，则发送方公布接收方有测量结果的位置所对应的随机序列，接收方由此恢复出信息序列；如果信道不安全，窃听者所获得的只是随机的发送序列，信息序列仍然是安全的.此协议与双向通信协议相比具有传输效率高、 易于实现等优点. 关键词： 量子密码 量子安全通信 单光子 单向通信     

双包层大模场面积保偏掺镱光子晶体光纤研究

采用改进的化学气相沉积法和溶液掺杂法制备出掺镱石英光纤预制棒,以该预制棒为有源纤芯制备芯区直径约为30μm的双包层保偏掺镱光子晶体光纤.模拟计算得到该保偏光纤的模场面积约232μm2,双折射系数B为5×10-5.利用该光纤分别进行了脉冲激光和连续激光的放大测试实验,在国内首次实现了高效率的飞秒激光放大,2 m长的光子晶体光纤可得到1.64 W的激光输出,激光放大斜率效率为49.8%.同时5 m长的光纤还能够实现8.12 W的连续激光放大输出,斜率效率达到55.9%,具有较高的斜率效率.此外,该光纤消光比约10 dB,具有良好的保偏特性.     

含载体D2EHPA的更新型支撑液膜体系对三价钆的分离

研究了以聚偏氟乙烯膜为支撑体,二-（2-乙基己基）磷酸(D2EHPA)为流动载体,煤油和D2EHPA的混合溶液作为膜溶液,膜溶液和解析剂HC1溶液组成更新相的更新型支撑液膜(RSLM)中Gd(Ⅲ)的分离行为；考察了料液pH、更新相HC1浓度、膜溶液与HC1溶液体积比、不同载体浓度对Gd(Ⅲ)分离的影响,得出了Gd(Ⅲ)最优分离条件为:更新相HC1溶液浓度4.00 mol/L,膜溶液与HC1溶液体积比4∶3,载体浓度控制在0.160 mol/L,料液相中pH为4.80.在最优分离条件下,当Gd(Ⅲ)的初始浓度为1.00×10-4 mol/L时,35 min Gd(Ⅲ)分离率达到95.7％.最后根据传质定律和界面化学理论提出了Gd(Ⅲ)在RSLM中的传质动力学方程.     

基于主元证据理论在车辆识别中的应用

车辆识别技术作为智能交通管理系统中的研究热点和难点;在车辆识别技术中,应用Dempster- Shafer证据组合规则融合冲突信息时会产生不合理的结果;基于修正证据源的思想,提出了一种新的权重系数确定方法,该方法从证据主元角度分析,确定各组证据主元,利用该主元求出证据相容度、可信度,进而确定证据权重系数；通过新的证据冲突衡量方法,确定冲突值,归一化权重,修正证据源,按ER规则融合各组证据对目标进行识别;仿真部分以实际路面车辆车型识别为算例,将该方法与其他方法对比,结果表明:该方法能更有效地融合高度冲突的证据,减小计算复杂度,目标识别的准确性提高20%。     

Combining layer-by-layer assembly with electrodeposition of silver aggregates for fabricating superhydrophobic surfaces

Taking advantage of the stability and penetrability of layer-by-layer (LbL) films, we develop a novel method to fabricate a branchlike structure of Ag aggregates on the matrix of a LbL polyelectrolyte multilayer by an electrodeposition technique. The morphology of Ag aggregates can be adjusted by electrodeposition time and potential. Moreover, after further chemisorption of a self-assembled monolayer of n-dodecanethiol, the as-prepared surface becomes superhydrophobic with a contact angle as high as 154 degrees and a tilt angle lower than 3 degrees.