Mapping the 5-50-kDa fraction of human amniotic fluid proteins by 2-DE and ESI-MS

This report presents a proteomic analysis and provides a reference map of the 5-50-kDa components of normal amniotic fluid collected in gestational weeks 16-18. Early amniocentesis samples were pooled and proteins with molecular mass lower than albumin were separated by gel filtration chromatography. The 2-DE protocol was optimized for the separation of the small proteins and peptides in the fraction of interest. A total of 132 Coomassie blue-stained protein spots were analyzed, following in-gel tryptic digestion, by ESI-MS/MS and 49 different gene products were identified. The treatment with alkaline phosphatase caused the shift of the phosphoisoforms of insulin-like growth factor-binding protein-1 and of the N-terminal osteopontin fragment. Of the 33 full-length proteins identified in the 2-DE profile, 23 had not been previously detected in the amniotic fluid and, of these, 22 are not present in the human plasma proteome under physiological conditions. Fragments of 16 larger proteins were identified and the sequence coverage data revealed that several correspond to autonomous domains that may have biological roles on their own. Several of the detected proteins and peptides appear to be involved in critical regulatory processes associated with placentation and early development, thus representing potential markers of various physiological or pathological conditions.     

广义几何规划的灵敏度分析及其在起重机结构优化设计中的应用

简述了广义几何规划灵敏度分析的原理,提出了一个解决大困难度几何规划灵敏度分析的实用算法,并以L型龙门起重机的优化数学模型为实例,分析了起重量、跨度和金属材料等参数发生扰动时对模型最优解的影响。其结果对实际工程设计有较大指导作用。     

活性氧化铝微粉对RH浸渍管浇注料性能的影响

以电熔白刚玉和电熔致密刚玉为主要原料 ,研究了活性α Al2 O3微粉对RH浸渍管浇注料的施工性能 (振动流动度 )、强度及抗渣性能的影响。研究表明 :添加适量活性α Al2 O3微粉能提高RH浸渍管用Al2 O3-MgO浇注料在高、中、低温下处理后的强度 ,并且能有效地提高浇注料的抗渣性能。但活性α Al2 O3微粉对浇注料的施工性能不利 ,且施工温度越高 ,其影响越显著。     

MgO-SiC-C材料的抗渣性能研究

以电熔镁砂、碳化硅、鳞片石墨(w(C)>97%)、铝粉(≤0.088mm,w(Al)>98%)和硅粉(≤0.088mm,w(Si)>98%)为主要原料,按w(电熔镁砂)=81%,w(SiC)=10%,w(鳞片石墨)=4%,w(铝粉 硅粉)=5%的组成配料,以酚醛树脂为结合剂,压制成125mm×25mm×25mm的MgO-SiC-C试样,在220℃干燥24h后采用感应炉法进行了抗转炉终渣试验,并对抗渣试验后试样进行了XRD、SEM和EDAX分析。结果发现熔渣对MgO-SiC-C试样的侵蚀和渗透并不显著,试样的侵蚀速率为0.25~0.3mm·h-1;抗渣试验后试样原质层主要组成为MgO、SiC和MgO·Al2O3;在与熔渣接触后,SiC被氧化成SiO2,由此导致在试样和熔渣间形成一高粘度的液相反应层,有效地减轻了试样受熔渣渗透和侵蚀的程度,提高了试样的抗渣能力。     

偏氯乙烯—氯乙烯悬浮共聚竞聚率和共聚物组成

在不同温度下测定了偏氯乙烯-氯乙烯悬浮共聚的竞聚率,剖析了共聚物组成随转化率的变化规律,根据45℃下测得的竞聚率,应用单体组成-转化率的普适积分式和简化积分式计算了共聚物平均组成,与实验值吻合。在适当转化率下终止聚合反应,可望获得组成分布不宽的共聚物。     

工业CT图像管道拟合

研究了工业CT图像序列中工件内部管道的拟合方法。在利用Facet模型提取管道边缘的基础上,将三维圆柱面、椭圆柱面管道的拟合转化为中心轴截面上的二维轮廓曲线圆、椭圆的拟合,与传统的三维曲面拟合相比,效率更高。通过对实际的发动机工业CT图像进行实验,结果表明该方法可以较准确地获取工件内部管道的几何参数,为基于工业CT的逆向工程打下基础。     

Aμ-MAC: 一种自适应的无线传感器网络MAC协议

结合基于竞争和调度机制的混合型方案是高效的无线传感器网络MAC协议的重要解决思路. μ-MAC是一种典型的混合型MAC协议, 本文在深入研究μ-MAC的基础上, 提出一种自适应的混合型协议Aμ-MAC. 它针对动态流量的数据采集型应用, 解决了μ-MAC中动态拓扑适应性及时钟同步问题, 并提供了良好的流量自适应性. 仿真结果表明, Aμ-MAC增强了协议的扩展性和适应性, 具有更好的网络生存能力, 而保留了与μ-MAC相近的节能效率和时延性能.     

Glass formation of ternary Sm-based Sm-Al-Co bulk metallic glasses

Ternary Sm-based Sm-Al-Co alloys at specific compositions designed using an e/a- and cluster-related criteria exhibit high glass forming abilities and form bulk glassy rods of 3 mm in diameter by a copper mold suction-casting method. Four composi- tions of bulk metallic glasses (BMGs) are Sm50Al25Co25, Sm52Al24Co24, Sm54Al23Co23 and Sm56Al22Co22, which all satisfy a constant conduction electron concentration of 1.5. Among them, the BMG exhibiting the largest reduced glass transition temperature (Trg) is Sm50Al25Co25, which reaches 0.648. The glass transition temperature Tg and the onset crystallization temperature Tx of this alloy are respectively 579 and 640 K at a heating rate of 20 K/min.     

DDoS下的TCP洪流攻击及对策

分布式拒绝服务攻击(DDoS)是近年来出现的一种极具攻击力的Internet攻击手段,而TCP洪流攻击是其最主要的攻击方式之一。本文提出了一种针对TCP洪流攻击的本地攻击检测-过滤LADF机制,其部署于受害者及其上游ISP网络。该机制综合使用了一种基于信息熵的异常检测技术、SYN-cookie技术和“红名单”技术来检测攻击报文,最终结合新型防火墙技术,构建起一个完善的本地DDoS防御系统。     

一种优化NTRU公钥密码体制

主要阐述了一个优化的NTRU公钥密码体制。通过对参数的选取及多项式的优化改进,这个优化的NTRU公钥密码体制与原体制及其他公钥密码体制相比较具有如下优点:算法更加简洁,密钥的生成简单。优化后的算法保留了原有的优点,同时加、解密速度提高了,其抗攻击能力也有明显的提高。此方案将有很好的研究价值与应用前景。