超高效液相色谱-串联质谱法测定大豆中异黄酮素含量

目的 以染料木黄酮、大豆苷元和黄豆黄素的含量为指标,建立超高效液相色谱-串联质谱测定大豆中异黄酮素总量的方法。方法 样品用乙醇-水(3+1,V/V)提取,经过β-葡萄糖苷酶水解后,用Acquity UPLC?BEH C18柱(2.1 mm×100 mm, 1.7μm)分离,以甲醇和0.1%甲酸溶液(含5 mmol/L乙酸铵)作为流动相进行梯度洗脱,电喷雾负离子模式(ESI-)电离,多反应监测模式进行检测。结果 染料木黄酮、大豆苷元在5.0～500μg/L范围内线性关系良好(r>0.995),方法的检出限分别为2.7、4.0 mg/kg,在300.0、600.0、1 200 mg/kg添加水平的平均回收率为89.4%～102.2%,相对标准偏差(n=6)为1.5%～4.6%;黄豆黄素在0.5～50.0μg/L范围内线性关系良好(r>0.995),方法的检出限为0.6 mg/kg,在30.0、60.0、120.0 mg/kg添加水平的平均回收率为85.7%～104.0%,相对标准偏差(n=6)为1.3%～2.8%。结论 该方法简单、灵敏、准确可靠,适用于大豆中异黄酮素含量的测定...     

含多端柔性直流输电系统的交直流电网动态特性分析

根据半桥式模块化多电平换流器(MMC)的数学模型和控制策略,搭建出基于PSCAD/EMTDC的多端柔性直流输电系统(MMC-MTDC)仿真模型.设计了适合于交直流耦合电网的MMC-MTDC多级控制系统,包括阀组级控制器、换流站级控制器和系统级控制器,并进行了交直流电网暂态稳定分析.在建立的仿真系统中模拟交流电网事故、直流线路故障、冲击负荷等多种苛刻运行条件,以校验MMC-MTDC接入交流电网后的动态响应特性.仿真结果表明:各级控制器间的相互配合使得所构建的MMC-MTDC在交流电网故障情况下具备送端转移的能力;系统在任意一端换流站故障退出后仍具备稳定运行的能力;在MMC-MTDC发生直流线路故障退出运行后,交流电网仍能保持稳定运行.     

常数轮理性秘密分享机制

基于重复博弈的理性秘密分享机制,首先由Maleka和Shareef提出,他们认为不存在常数轮的重复理性秘密分享机制（Repeated Rational Secret Sharing Scheme,RRSSS）。然而,无限轮RRSSS效率低下,不具备应用价值。为了实现高效的常数轮RRSSS,为参与者设置了不同的类型,提出了不完全信息下的常数轮RRSSS机制,并证明了机制的有效性。与其他理性秘密分享方案比较,在给定条件下,新方案在（纳什）均衡、期望执行时间和通信信道方面均具有优势。     

差分隐私二维数据流统计发布

目前关于差分隐私数据流统计发布的研究仅考虑一维数据流,其方法无法直接用于解决二维数据流统计发布中可能存在的隐私泄露问题.针对此问题,首先提出面向固定长度二维数据流的差分隐私统计发布算法--PTDSS算法.该算法通过单次线性扫描数据流,以较低空间消耗计算出满足一定条件的二维数据流元组的统计频度,并经过敏感度分析添加适量的噪声使其满足差分隐私要求;接着在PTDSS算法的基础上,利用滑动窗口机制,设计出面向任意长度二维数据流的差分隐私连续统计发布算法--PTDSS-SW.理论分析与实验结果表明,所提算法可安全地实现二维数据流统计发布的隐私保护,同时统计发布结果的相对误差在10%~95%.     

毛霉型豆豉后发酵阶段蛋白质水解产物的生成及影响因素

采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、反相高效液相色谱等方法对毛霉型豆豉后发酵过程中蛋白质及其水解产物的变化情况进行研究,对各阶段蛋白质水解产物与不同因素指标的相关性进行分析,并采用APIZYM系统对毛霉所产胞外酶进行半定量检测。结果表明:蛋白质最终水解产物的分子质量主要集中在11~20 kD之间,后发酵0~7 d蛋白质分子质量下降迅速,且此阶段多肽成分发生较大改变,7~42 d主要引起的是多肽含量的变化;总酸含量与蛋白质水解物生成的相关性最高,相关系数为0.972,其次为褐变强度,再次为还原糖含量;API ZYM系统检测出毛霉可产生6种胞外酶。     

BF6M1015C柴油机高压共轨系统中的共轨管设计

研究了BF6M1015C柴油机高压共轨喷油系统方案,并进行了共轨管的匹配设计;采用AMESim软件仿真了共轨管结构参数,分析了共轨管的布置结构、共轨管形状和容积对轨压建立、轨压跟随和轨压波动的影响,并最后根据仿真结果对共轨管进行了结构设计。     

唐口煤矿紧急避险系统的建设

针对唐口煤矿的生产技术条件,从提升矿井安全保障能力出发,设计了唐口煤矿紧急避险系统;紧急避险系统由永久避难硐室、临时避难硐室和可移动式救生舱组成;井下紧急避险设施的设计和建设要充分考虑采掘接续计划、围岩和地压情况及安全生产实际,要与供氧系统子系统、环境监测监控系统等有效结合;井下紧急避险系统的应用,可增强井下职工的安全感,有效保障煤矿企业的安全运营。     

Edge-cloud-enabled matrix factorization for diversified APIs recommendation in mashup creation

World Wide Web - A growing number of web APIs published on the Internet allows mashup developers to discover appropriate web APIs for polishing mashups. Developers often have to manually pick and...     

Fairness in secure computing protocols based on incentives

Cloud computing is based on utility and consumption of computer resources. To solve the security issues in cloud computing, secure computing protocols are often used. Recently, rational parties as a new kind of parties are proposed, who wish to maximize their utilities in secure computing protocols. The utility definitions in most previous rational secure computing protocols derive from prisoner’s dilemma game (PD game). In two-party rational computing protocols, parties decide to send their shares according to their utilities. Recently, we revisit the incentives for rational parties in secure computing protocols and give new utility definitions according to them. We find that the new utility definition is not similar to PD game any more. We discuss two-party and multi-party cases, respectively, and prove that parties have incentives to send their share to others. Furthermore, we also prove that parties can maximize their utilities in both cases.     

Evolution of the Raman spectrum of graphene grown on copper upon oxidation of the substrate

Significant changes in the Raman spectrum of single-layer graphene grown on a copper film were observed after the spontaneous oxidation of the underlying substrate that occurred under ambient conditions. The frequencies of the graphene G and 2D Raman modes were found to undergo red shifts, while the intensities of the two bands change by more than an order of magnitude. To understand the origin of these effects, we further characterized the samples by scanning tunneling microscopy （STM）, scanning tunneling spectroscopy （STS）, and atomic force microscopy （AFM）. The oxidation of the substrate produced an appreciable corrugation in the substrate without disrupting the crystalline order of the graphene overlayer and/or changing the carrier doping level. We explain the red shifts of the Raman frequencies in terms of tensile strain induced by corrugation of the graphene layer. The changes in Raman intensity with oxidation arise from the influence of the thin cuprous oxide film on the efficiency of light coupling with the graphene layer in the Raman scattering process.