多层PCB介质基板中嵌入高K材料对信号完整性的影响

采用数值仿真分析了多层PCB的电源/地平面中嵌入高K材料对过孔转换信号完整性的影响。研究了电源/地平面间的介质层整体采用高介电常数(高K)材料时信号过孔的S参数,并提出了两种局部添加高K材料的方法,一是在过孔周围布置一个包围过孔的介质柱,二是在过孔周围均匀布置若干个小介质柱。计算结果表明,介质层整体采用高K材料会引起较多的谐振,信号完整性变差;当嵌入介质材料的介电常数足够大时,在过孔周围局部嵌入高K材料的方法可明显增强信号完整性,其中,包围过孔的单个介质柱在高频时的性能良好,而在过孔周围嵌入多个小介质柱在低频时的效果较好。     

Security-enhanced live migration based on SGX for virtual machine

The virtual machine may face the problem of information leakage in live migration.Therefore,a dynamic memory protection technique SGX was introduced and a security enhancement live migration method based on KVM environment was proposed.Firstly,on both sides of migration,a hardware-isolated secure execution environment centered SGX was built.It guaranteed the security of operations like encryption and integrity measurement and also ensured the security of private data.An encrypted channel to transfer migration data based on the remote attestation between the secure execution environments of both migration sides was constructed.And the mutual authentication of both sides’ platform integrity was realized.Finally,the security enhancement effect and did the experiment was analyzed.The results shows that the introduction of SGX won’t cause much negative effect to the migration performance.     

Mango (Mangifera indica L.) Polyphenols: Anti-Inflammatory Intestinal Microbial Health Benefits,and Associated Mechanisms of Actions

Mango is rich in polyphenols including gallotannins and gallic acid, among others. The bioavailability of mango polyphenols, especially polymeric gallotannins, is largely dependent on the intestinal microbiota, where the generation of absorbable metabolites depends on microbial enzymes. Mango polyphenols can favorably modulate bacteria associated with the production of bioactive gallotannin metabolites including Lactobacillus plantarum, resulting in intestinal health benefits. In several studies, the prebiotic effects of mango polyphenols and dietary fiber, their potential contribution to lower intestinal inflammation and promotion of intestinal integrity have been demonstrated. Additionally, polyphenols occurring in mango have some potential to interact with intestinal and less likely with hepatic enzymes or transporter systems. This review provides an overview of interactions of mango polyphenols with the intestinal microbiome, associated health benefits and underlying mechanisms.     

Sr1.7Ba1.3MgSi2O8:Eu2+, Mn2+ 荧光玻璃陶瓷材料制备与表征 ——稀土化学课程研究性综合实验设计

结合稀土化学课程中的稀土发光材料和光学农业背景下研究生材料研究相关专业的特点,开设"Sr_(1.7)Ba_(1.3)MgSi_2O_8∶Eu~(2+), Mn~(2+)荧光玻璃陶瓷材料制备与表征"研究性综合实验项目,通过实验原理阐述、研究思路和方法的确立、材料制备、测试表征、数据处理等环节,使研究生充分掌握专业知识,并实践到研究工作中去,同时树立良好的学术诚信品德品质。实践表明,该实验项目选题针对性强,有助于提高学生的综合实验技能,有利于培养学生的基本科研素养,从而达到提高教育和教学质量的目的。     

行波折反射法在信号完整性的研究中的应用

近年来随着高速数字电子系统运行速度的不断增加,研究有损传输线的暂态过程已成为高速电路信号完整性分析的重要内容。行波折反射理论已被成功用于分析理想无损均匀传输线,如何运用该方法分析有损传输线有待进一步研究。本文将衰减因子引入行波折反射理论,分析有损均匀传输线暂态过程,计算结果准确,因此该方法是有效的。     

一种保护软件可信运行解决方案

软件的可信运行是软件质量的关键因素,一个软件具有可信性是指其提供的服务总与用户的预期相符,为了保护软件的可信运行提出一种解决方案:通过在传统硬件计算平台上添加认证模块验证软件的完整性的方法保护软件的可信运行.认证模块使用非对称加密算法验证软件的数字签名,并根据认证结果控制主机软件的运行流程.一旦主机软件被篡改,认证模块就会锁住主机复位信号停止软件启动.     

高速数字电路PCB中串扰问题的研究与仿真

针对高速数字电路PCB中传输线间串扰的严重性,从精确分析PCB中串扰噪声的角度出发,在传统的双线耦合模型的基础上,采用了一种三线串扰耦合模型。该模型由两条攻击线和一条受害线组成,两条攻击线位于受害线的两侧,线间采取平行耦合的方式。利用信号完整性仿真软件Hyperlynx对受害线上的近端串扰噪声和远端串扰噪声进行了仿真。仿真结果表明,不同的传输模式和传输线类型、信号层与地平面的距离、耦合长度、传输线间距和信号上升/下降沿等因素会对受害线上的近端串扰和远端串扰产生较大的影响。在分析仿真结果的基础上,总结出了高速PCB设计中抑制串扰的有效措施,对高速数字电路设计有一定的指导意义。     

Securing Cloud Storage by Remote DataIntegrity Check with Secured Key Generation

In recent decades, a number of protocols for Remote data integrity checking (RDIC) have been proposed.Identity (ID) based RDIC protocols are constructed to guarantee cloud data integrity and data privacy. The known protocols for RDIC always assume that the Private key generator (PKG) is a trusted one, but in real-world applications by corrupt PKG, malicious Cloud server (CS) can easily cheat the third party auditor that the data owner's outsourced data are kept safe through the data has been deleted or altered. In this paper, we explore the novel model of RDIC with untrusted PKG and malicious CS, by employing the partial key method and Authentication, authorization, accounting (AAA) service. We construct a new ID-based RDIC, which provides the ID revocation and key updation. The experimental evaluations show that our scheme is more efficient than known ones.     

地平面的分割

一个完整的地平面能减少电路板的EMI和串扰问题。在数模混合布板时,数字电路的同步开关噪声往往会影响敏感的模拟电路。分割的地平面能够提供高的噪声隔离度,但同时也会引起另外的一些EMI问题。本文就如何正确的分割地平面以及为什么这样分割进行了讨论,并给出了地分割的相应设计原则。     

RapidIO高速串行总线的信号完整性仿真

采用最先进的3D电磁场仿真软件对RapidIO高速串行总线进行了板级信号完整性仿真,在前仿真中对关心的设计参数进行了有效评估,形成了可信赖的指导数据;后仿真对实际设计数据进行了验证,修正了不理想的设计参数。仿真手段彻底改变了依靠经验和反复试验的设计方法,成为高速串行传输技术中不可或缺的设计手段。