Quality control criteria for solid-contact, solvent polymeric membrane ion-selective electrodes

After a long history and conflicting views, solid-contact (SC) solvent polymeric membrane ion-selective electrodes (ISEs) emerged as reliable potentometric-sensing devices with unique advantages. From the large variety of proposed SCs inherently conductive polymers emerged as the materials of choice. In our view, the most attractive feature of SC ISEs is their compatibility with thin- and thick-film microfabrication technologies that can provide cheap, mass-produced sensors and sensor arrays that can be integrated with the measuring, data acquisition, and control electronics in a straightforward way. However, despite the impressive properties of certain SC electrodes and their potential advantages, they remained primarily in the research laboratories. To make the jump from the research laboratories into commercial devices, it would be essential to prove that miniaturized SC ISEs can indeed match or surpass the performance characteristics of the conventional, liquid-contact macroelectrodes. In addition, it would be important to settle on the quality control criteria and testing protocols for assessing the performance characteristics of SC electrodes. It could help in interpreting the sometimes-inconsistent experimental data. Once cheap, miniaturized, SC ISEs will mach the performance characteristics of macroscopic-size electrodes, it is expected to have an important impact in a variety of applications requiring robust, maintenance-free, or single-use ISEs, e.g., in homecare or bedside diagnostics, environmental analysis, and quality control assessment. In addition, reliable SC ISEs are expected to revitalize the field of ion-selective field effect transistors and open new possibilities in combination with nanowire-based devices.     

Glucose biosensor based on the layer-by-layer self-assembling of glucose oxidase and chitosan derivatives on a thiolated gold surface

This work examines in deep the analytical performance of an example of “first-generation” microdevices: capillary electrophoresis microchip (CE) with end-channel electrochemical detection (ED). A hydroquinone and arbutin separation strategically chosen as route involving pharmaceutical-clinical testing, public safety and food control scenes was carried out. The reproducibility of the unpinched electrokinetic protocol was carefully studied and the technical possibility of working indiscriminately and/or sequentially with both simple cross-injectors was also demonstrated using a real sample (R.S.D.'s less than 7%). The robustness of the injection protocol allowed checking the state of the microchip/detector coupling and following the extraction efficiency of the analyte from real sample. Separation variables such as pH, ionic strength and, separation voltage were also carefully assayed and optimized. Analyte screening was performed using borate buffer (pH 9, 60 mM) in less than 180 s in the samples studied improving dramatically the analysis times used for the same analytes on a conventional scale (15 min), with good precision (R.S.D.'s ranging 5-10%), accuracy (recoveries ranging 90-110%) and acceptable resolution (Rs ≥ 1.0).In addition, the excellent analytical performance of the overall analytical method indicated the quality of the whole analytical microsystem and allowed to introduce the definition of robustness for methodologies developed into the “lab-on-a-chip” scene.     

Formal modeling and analysis of a narrow bandwidth protocol for establishing and terminating connections

The paper presents a formal modeling and analysis of a protocol for narrow bandwidth channels of service connection establishment and termination. The protocol is characterized by state traces and formally verified by a theorem proving system PVS. Relevant properties are specified and verified in terms of inductive principles. The effectiveness of the proposed method is evidenced by the elaborate analysis which unveils a subtle bug in the initial protocol implementation. The approach is scalable for an arbitrary number of agents.     

基于贝叶斯网的网络故障监测方法

提出了一种基于贝叶斯网络的智能故障监测方法．通过有限混合模型对单个MIB变量的行为进行建模，将基于模型参数产生的残差用以描述MIB变量的状态；把观测得到的各MIB变量的信息经由贝叶斯网络加以融合，从而计算出网络出现故障的概率，包括未知的和不可预见的故障．实验中，在故障发生前约5mm网络异常的后验概率超过0．5，表明该方法能够在故障发生以前发现网络异常行为．     

TCP在光突发交换试验网络中性能的实验研究

在光突发交换试验网络中对TCP的性能进行了实验研究.首先研究了丢包对网络性能的影响,表明突发包丢失将导致TCP吞吐量的快速下降,并且丢包率越高,可用的TCP传输带宽越窄.然后分别详细研究了OBS试验网络中的延时损伤和报文段关联增益,以及对TCP传输性能的影响.最后综合考虑这些因素.实验结果表明,在本OBS试验网络中存在一个不随丢包率变化的最优化突发包组装时间250us使得可用TCP带宽最大化.为了最大限度地提高TCP的传输性能,组包时间应该选择等于或稍大于这个最优值.     

Compact eye-safe laser sources based on OPOs with KTP or PPKTP crystals

We report on compact eye-safe nanosecond laser sources emitting in the 1.5 μm wavelength range based on non-critically phase-matched parametric interaction in optical parametric oscillators (OPOs) with KTP and periodically poled KTP (PPKTP) crystals, pumped by the fundamental frequency of Nd:YAG lasers. As much as 250 μJ signal pulse energy at 1.5 μm wavelength, 6.5 ns FWHM pulse-width, has been obtained in a PPKTP-OPO, extracavity pumped by a Nd:YAG microlaser oscillator–amplifier at 650 μJ pump pulse energy, 8 ns pulse-width. A single signal pulse of 2.7-mJ output energy at 1.57 μm wavelength, less than 5 ns pulse-width, was generated in a KTP-OPO, intracavity pumped by a passively Q-switched Nd:YAG laser.     

基于差分相移键控协议的双向量子密钥分配系统研究

采用差分相移键控(DPSK)协议分析了双向量子密钥分配(QKD)系统的性能，比较了BB84协议、BBM92协议和DPSK协议的安全通信速率与距离的关系，并对协议对抗一些攻击的安全性进行了分析，结果表明DPSK协议对长距离QKD系统非常实用，具有超过200 km的通信距离和较高的通信速率.     

搜索引擎Web API框架设计研究

传统的基于网页方式的搜索引擎服务不能很好地满足用户个性化的需求,搜索引擎Web API概念的提出较好的解决了这一问题.本文提出了一种基于SOAP和WSDL标准的搜索引擎Web API的构架模型.该构架模型的接口由五大部分组成,内容涵盖了用户自定义搜索条件的各项参数以及返回结果剥离所需的各项参数.采用SOAP和WSDL标准保证了该接口跨语言、跨平台特性.文章系统地介绍了框架的构造、功能,并对接口方法以及参数定义进行了详细的说明.     

850nm光纤中1.1km量子密钥分发实验

在850nm波长完成了一个全光纤量子密钥分发系统原型.该系统以单光子为信息载体,以光纤为量子信道,在通信双方建立起共享的密钥,从而完成量子密钥的分发,其安全性由量子力学基本原理——不确定性原理和量子不可克隆定理所保证.所采取的信息调制方式为相位调制,通信协议采取BB84协议.通信距离为1.1km,有效数据传送速率为3bit/s,误码率为9%左右