基于IXP2800处理器的IGMP Snooping协议的设计与实现

介绍了IGMP Snooping在Intel IXA架构上的设计方案,并通过对组播查询报文的监听,在IXP2800网络处理器上实现了消除冗余组播报文和快速转发组播报文的目的。     

基于IXP2400的双栈路由器的设计和实现

IPv4 over IPv6(简称4over6)机制是由清华大学提出来的一种用于解决IPv4网络通过IPv6 主干网而互通的机制.通过详细分析其在Solaris系统的实现,结合网络处理器的高速可编程特性,在IXP2400中实现了4over6机制,并且为了用户可以直接访问IPv6网络,添加了NAT-PT机制,实现了一整套的基于网络处理器的IPv4向IPv6的过渡机制.     

基于监视器系统的内部网络安全策略

为了解决内网信息泄露问题,提出了一种新的内网安全策略。该策略有两个特点:一是采用层次化的手段对信息进行分级,二是引入了监控器这个部件,监控器对内网各网络部件之间的通信过程实行控制,动态地隔离涉密的主机。新的安全策略在保障信息安全的前提下,有效地提高了资源使用效率。基于该策略设计了一种基于IntelIXP2400芯片的监视器系统。实验结果表明,凭借IXP2400芯片的强大处理能力,该监检测系统可以高效地处理Gb/s速率的网络数据流。     

Teflon AF 2400管冷蒸气发生-原子荧光法分析烟草中的痕量汞

采用具有高气体渗透性和紫外光透过性的无定形聚四氟乙烯管(Teflon AF-2400)作为蒸气发生原子荧光系统的气液分离器和检测池,建立了微型化汞蒸气发生原子荧光检测系统。考察了Teflon AF-2400管长度、还原剂种类和浓度、酸介质种类和浓度、进样流速以及氩气流速对测量体系的影响。在优化实验条件下,该方法的线性范围为0.07~10μg/L(r=0.998 0),检出限为0.02μg/L,相对标准偏差(n=11)为3.3%。该系统体积小、样品消耗少、灵敏度高。方法已成功应用于卷烟样品中汞含量的检测,回收率为97%~102%。     

Teflon AF-2400管冷蒸气发生-原子荧光法分析烟草中的痕量汞

采用具有高气体渗透性和紫外光透过性的无定形聚四氟乙烯管(Teflon AF-2400)作为蒸气发生原子荧光系统的气液分离器和检测池,建立了微型化汞蒸气发生原子荧光检测系统.考察了Teflon AF-2400管长度、还原剂种类和浓度、酸介质种类和浓度、进样流速以及氩气流速对测量体系的影响.在优化实验条件下,该方法的线性范...     

Addition-type polynorbornene with Si(CH3)3 side groups: Detailed study of gas permeation and thermodynamic properties

Polymerization of norbornene bearing Si(CH₃)₃ groups in the five position with the opening of double bonds was performed. By accurate selection of the ratios catalyst/co-catalyst and monomer/catalyst the samples with increased molecular mass (about 400,000) were obtained. Transport parameters of this, addition type poly(trimethylsilyl norbornene) (PTMSN) were measured using the gas chromatographic and mass spectrometric methods for different gases (H₂, He, O₂, N₂, CO₂, CH₄, C₂H₆, C₃H₈ and n-C₄H₁₀). Temperature dependence of the permeability coefficients (P) indicated that low activation energies of permeation (E_P) and diffusion (E_D) are characteristic for PTMSN. In some cases (CO₂, C₂H₆) negative E_P values were observed. Thermodynamics of vapor sorption in this polymer was studied using the inverse gas chromatography method. It was shown that PTMSN is characterized by very large solubility coefficients S similar to those of poly(trimethylsilyl propyne) (PTMSP). The comparison of the P, D, and S values of these highly permeable polymers showed that the greater permeability of PTMSP is determined by the larger D values. Application of different approaches for the determination of the size of microcavities in PTMSN indicated that this polymer is characterized by large size of microcavity (800–1200 ?³).     

基于CRM2400的短距离无线数据传输

提出了一个基于CRM2400的短距离无线数据传输系统，给出了该系统的组成、硬件电路和软件流程图．CRM2400在单片机Atmega16的控制下，工作在突发模式，可实现全双工通信．进行了CRM2400的初始配置。实现了Atmega16和CRM2400之间的SPI接口．实验表明，系统运行良好，功能易于扩展．     

Sorption and diffusion of organic vapors in amorphous Teflon AF2400

Vapor sorption in amorphous Teflon AF2400 of various organic solutes was studied in a wide range of activity at 25 °C by means of the gravimetric technique. The sorption isotherms of hexane, toluene, and chloroform were shown to be concave to the pressure axis and are consistent with the dual mode sorption model (DMS). The parameters of the DMS model k_D and b reveal a linear correlation with squared critical temperature of solutes T. The third model parameter, the Langmuir sorption capacity C′_H decreases when the size of solutes (critical volume) increases. Sorption isotherms of methanol and ethanol were shown to be convex to the pressure axis and are consistent with cluster formation in this strongly hydrophobic polymer. Concentration‐dependent diffusion coefficients D were determined using a linear implicit difference scheme in analysis of sorption kinetics. It was shown that D values increase exponentially with concentration for all the solutes, except alcohols for which exponential reduction of D(C) was observed. The partitioning of the thermodynamic and mobility contributions in D indicated that the reduction of D values of alcohols is consistent with clustering phenomena in AF2400. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 832–844, 2006     

Absorbance characteristics of a liquid-phase gas sensor based on gas-permeable liquid core waveguides

The absorbance characteristics and influential factors on these characteristics for a liquid-phase gas sensor, which is based on gas–permeable liquid core waveguides (LCWs), are studied from theoretical and experimental viewpoints in this paper. According to theory, it is predicted that absorbance is proportional to the analyte concentration, sampling time, analyte diffusion coefficient, and geometric factor of this device when the depletion layer of the analyte is ignored. The experimental results are in agreement with the theoretical hypothesis. According to the experimental results, absorbance is time-dependent and increasing linearly over time after the requisite response time with a linear correlation coefficient r² > 0.999. In the linear region, the rate of absorbance change (RAC) indicates improved linearity with sample concentration and a relative higher sensitivity than instantaneous absorbance does. By using a core liquid that is more affinitive to the analyte, reducing wall thickness and the inner diameter of the tubing, or increasing sample flow rate limitedly, the response time can be decreased and the sensitivity can be increased. However, increasing the LCW length can only enhance sensitivity and has no effect on response time. For liquid phase detection, there is a maximum flow rate, and the absorbance will decrease beyond the stated limit. Under experimental conditions, hexane as the LCW core solvent, a tubing wall thickness of 0.1 mm, a length of 10 cm, and a flow rate of 12 mL min⁻¹, the detection results for the aqueous benzene sample demonstrate a response time of 4 min. Additionally, the standard curve for the RAC versus concentration is RAC = 0.0267 c + 0.0351 (AU min⁻¹), with r² = 0.9922 within concentrations of 0.5–3.0 mg L⁻¹. The relative error for 0.5 mg L⁻¹ benzene (n = 6) is 7.4 ± 3.7%, and the LOD is 0.04 mg L⁻¹. This research can provide theoretical and practical guides for liquid–phase gas sensor design and development based on a gas-permeable Teflon AF 2400 LCW.     

基于IXP2400的双栈路由器的设计和实现

IPv4 over IPv6（简称4over6）机制是由清华大学提出来的一种用于解决IPv4网络通过IPv6主干网而互通的机制.通过详细分析其在Solaris系统的实现,结合网络处理器的高速可编程特性,在IXP2400中实现了4over6机制,并且为了用户可以直接访问IPv6网络,添加了NAT-PT机制,实现了一整套的基于网络处理器的IPv4向IPv6的过渡机制.