乳清蛋白肽的酶法制备、分离纯化及活性评价

以抗氧化活性及蛋白质回收率为筛选指标对乳清蛋白肽酶解工艺进行优化,用层析柱对酶解液进行逐级分离纯化,并对其分子质量进行检测.研究结果表明:利用胰酶、复合风味蛋白酶、木瓜蛋白酶和碱性蛋白酶酶解制备乳清蛋白肽,最佳用酶为碱性蛋白酶、最适底物含量为4.0%、最适加酶量为8000U/g、最佳酶解时间为4h;酶解液经DEAE-52纤维素层析后得到的A组分抗氧化活性最好,其还原力为0.320 0±0.004 1,DPPH自由基清除率为6.58%±0.36%;A组分再经Sephadex G-15葡聚糖凝胶层析柱分离纯化后得到组分G,其DPPH自由基清除率为6.73%±0.083%;组分G的主要成分为分子质量378 u的肽段,其一级氨基酸组成为赖氨酸(Lys)、亮氨酸(Leu)及丝氨酸(Ser).     

具有移动汇聚节点的单跳传感器网络延迟分析

研究了具有移动汇聚节点情况下的单跳传感器网络的延迟特性.通过对单跳无线传感器网络的理论建模,分析了构成数据延迟的主要延迟类犁以及它们之间的相互关系.根据具体场景对延迟的显式表达进行了理论推导,并通过仿真结果验证了数学模型的正确性.该数学建模的方法为提升移动无线传感器网络的性能提供了理论依据.还分析了传输半径和移动速率对延迟的影响,可以看出移动策略对网络性能的影响最为明显,需要针对具体的应用来设计.     

无线多跳传感器网络中能量消耗均衡分簇策略

针对在无线多跳传感器网络中节点间能量消耗不均衡、中继节点容易过早失效的问题,基于几何规划提出一种自适应的分簇算法.该算法通过节点的能量水平和位置来调节其竞争簇头的概率,同时通过簇头的能量水平和离汇聚点的距离调节簇头"管辖"范围.仿真表明:本算法很好地均衡了网络能量开销,使得网络的生命周期延长了25%,稳定周期延长了50%.     

Highly stretchable and sensitive strain sensor based on silver nanowires/carbon nanotubes on hair band for human motion detection

In this work, a highly stretchable and sensitive strain sensor using silver nanowires(Ag NWs)/multi-walled carbon nanotubes(MWCNTs) on hair band is proposed. The fabrication process of such sensors enabled scalable and facile production with low cost by dipping hair band into Ag NWs/MWCNTs composites suspension. The sensing performance of the sensors was optimized by tuning the Ag NWs/MWCNTs mass ratio. The hair band based strain sensor with Ag NWs/MWCNTs mass ratio of 30 exhibited the best perf...     

The role of jumps in the agricultural futures market on forecasting stock market volatility: New evidence

In this study, we explore the effect of cojumps within the agricultural futures market, and cojumps between the agricultural futures market and the stock market, on stock volatility forecasting. Also, we take into account large and small components of cojumps. We have several noteworthy findings. First, large jumps may lead to more substantial fluctuations and are more powerful than small jumps. The effect of cojumps and their decompositions on future volatility are mixed. Second, a model including large and small cojumps between the agricultural futures market and the stock market can achieve a higher forecasting accuracy, implying that large and small cojumps contain more useful predictive information than cojumps themselves. Third, our conclusions are robust based on various robustness tests such as the realized kernel, expanding forecasts, different forecasting windows, different jump tests, and different threshold values.     

融合视惯传感数据的非接触式物体尺寸获取方法

从视觉数据和惯性测量单元(Inertial Measurement Unit, IMU)数据各自的特点出发,利用计算机视觉三维重建技术从视觉数据中恢复视觉传感器的六维位姿信息,分析计算惯性测量数据和视觉位姿数据的时空关系,实现融合视惯传感数据的场景重建及尺度估计,进而获取待测对象的绝对物理尺寸数据。上述方法在实验数据上取得了相对误差约为3%的非接触式物体尺寸估计结果,由于该方法无需在待测场景中嵌入额外标定物或辅助定位装置,具有较好的灵活性和适用范围。     

Resource Allocation in Public Healthcare: A Team-DEA Model

This paper combines the theory of teams and data envelopment analysis (DEA) to design a mechanism to optimally allocate resources in public healthcare. A statutory authority and the public hospitals under its governance are interpreted as a team, the members of which seek to operate efficiently under the shared institutional constraint that public healthcare is a public good. The individual public hospital exploits DEA to maximize own-payoff, subject to the team-condition that the payoff of each other public hospital does not fall and thereby subtract from the external effects created by the public supply of healthcare. The resulting team-DEA solution, which is shown to be both an individually-efficient and team-satisficing equilibrium and to be computable in terms of a convergent algorithm, can then be applied by the authority to determine the optimal allocation of resources in public healthcare. A case based on Chinese data is presented to illustrate the team-DEA model’s ready operationalization and computation.     

淬火分配处理对高碳钢组织、力学性能和磨损性能的影响

The present work employed the X-ray diffraction, scanning electron microscopy, electron backscattered diffraction, and electron probe microanalysis techniques to identify the microstructural evolution and mechanical and abrasive behavior of high carbon steel during quenching-partitioning treatment with an aim to enhance the toughness and wear resistance of high carbon steel. Results showed that, with the increase in partitioning temperature from 250 to 400°C, the amount of retained austenite (RA) decreased resulting from the carbide precipitation effect after longer partitioning times. Moreover, the stability of RA generally increased because of the enhanced degree of carbon enrichment in RA. Given the factors affecting the toughness of high carbon steel, the stability of RA associated with size, carbon content, and morphology plays a significant role in determining the toughness of high carbon steel. The analysis of the wear resistance of samples with different mechanical properties shows that hardness is the primary factor affecting the wear resistance of high carbon steel, and the toughness is the secondary one.     

S-激发剂对高钙粉煤灰潜在水硬性的激发

本文采用测定水化过程结合水量、XRD和 SEM等技术研究了纯高钙粉煤灰的水化及S—激发剂对高钙粉煤灰的激发作用。结果表明 ,高钙粉煤灰由于含有较多的 f Ca O,水化时产生较大的膨胀而使试样粉化、无一点强度 ,掺入 S—激发剂可较好地激发高钙粉煤灰的潜在水硬性 ,增加水化过程结合水量 ,从而使掺有 S—激发剂的高钙粉煤灰试样水化不同龄期后均有一定的强度