Comparison of ISO 14902:2001 with AOCS Ba 12a-2020 for determining trypsin inhibitor activity in protein products

For measuring trypsin inhibitor activity (TIA), there are two major official methods: American Oil Chemists Society (AOCS) method Ba 12a-2020 and International Organization for Standardization (ISO) 14902:2001. The former was recently approved. The two methods differ in sample preparation, extraction, colorimetric assay systems and TIA calculations. In this study, the two methods were symmetrically compared using three unique sets of samples: assorted protein products of soybeans, pulses, and grains; soybeans boiled for varied durations; and soy white flakes toasted for varied durations. For given samples, significant differences existed in TIA measured by the two methods, resulting from effects related to the assay systems and TIA calculations, not from the difference in sample preparation and extraction. When the same trypsin was used, TIA (in mg trypsin inhibited/g sample) measured by the two methods were highly correlated (r = 0.9973, n = 27), giving an equation of y = 0.5464x − 0.4887, where y represents ISO values and x for AOCS values. The line connecting ratios of ISO/AOCS in TIA and AOCS values remained relatively flat around 0.53 but started to curve down when TIA approached the lowest. Furthermore, for the same samples, TIA values measured by the ISO method decreased with increasing specific activity of trypsin used, while AOCS values remained consistent, leading to decreasing ratios of ISO/AOCS. Therefore, accurate and direct comparison of the two methods was impossible. It could not be resolved by simply changing ISO method's calculations as hypothesized earlier. Regardless, for most samples, ISO values were roughly about 55% of AOCS values.     

国外TOFD检测标准分析和比较

概述了超声波衍射时差法（TOFD），对目前世界上主要的七个TOFD检测标准或规范进行了分析和比较，归纳了其中十二个方面的异同点。为我国TOFD检测标准的制订和TOFD技术的发展提供参考。     

有效优化扩展I/O点提高PLC系统的性价比

在利用PLC对复杂化的设备进行控制及改造时,常常遇到PLC的I/O点数不够用的情况。本文从软件和硬件两方面介绍了PLC在实际应用中优化扩展I/O点的几种常规有效方法,这些方法可大大降低硬件成本,在机床电气控制及改造中具有很高的实用价值。     

75Se源γ射线透照工艺性能试验

通过透照试验,比较75Se源γ射线、192Ir源γ射线与X射线的照相特性,以及不同射线源与不同种类胶片和不同厚度增感屏的组合系统的照相灵敏度;测定了75Se源γ射线的透照厚度与灵敏度的关系,提出了75Se射线照相适用的厚度范围。     

白家河水库溢洪道侧槽水力设计

以白家河水库侧槽溢洪道为例,介绍其设计方案比选、总体布置、水力计算等,给出了其泄流能力、堰面曲线、泄槽临界水深、侧槽末端水深、侧槽末端底高程和侧槽水面线等水力计算方法和成果,为白家河水库侧槽溢洪道的设计提供了依据。     

Conditional diagnosability and strong diagnosability of shuffle-cubes under the comparison model

The growing size of multiprocessor systems increases the vulnerability to component failures. It is crucial to locate and replace faulty processors to maintain the system's high reliability. Processor fault diagnosis is essential to the reliability of a multiprocessor system and the diagnosabilities of many well-known networks (such as hierarchical hypercubes and crossed cubes [S. Zhou, L. Lin and J.-M. Xu, Conditional fault diagnosis of hierarchical hypercubes, Int. J. Comput. Math. 89(16) (2012), pp. 2152–2164 and S. Zhou, The conditional diagnosability of crossed cubes under the comparison model, Int. J. Comput. Math. 87(15) (2010), pp. 3387–3396]) have been investigated in the literature. A system is t-diagnosable if all faulty nodes can be identified without replacement when the number of faults does not exceed t, where t is some positive integer. Furthermore, a system is strongly t-diagnosable if it is t-diagnosable and can achieve (t+1)-diagnosability except for the case where a node's neighbours are all faulty. In addition, conditional diagnosability has been widely accepted as a new measure of diagnosability by assuming that any fault-set cannot contain all neighbours of any node in a multiprocessor system. In this paper, we determine the conditional diagnosability and strong diagnosability of an n-dimensional shuffle-cube SQ_n, a variant of hypercube for multiprocessor systems, under the comparison model. We show that the conditional diagnosability of shuffle-cube SQ_n (n=4k+2 and k≥2) is 3n?9, and SQ_n is strongly n-diagnosable under the comparison model.     

基于忆阻器的迟滞比较电路研究

研究了惠普忆阻器的电荷控制模型,并构建了其SimuIink模型,给出了相应的仿真结果。最后设计了一种基于忆阻器的迟滞比较电路,建立了其SimuIink仿真模型,分析了其仿真结果。此电路简单易用,能应用于多种电路,比如方波和锯齿波产生电路等。它在电路尺寸、电路功耗等方面都有优势。     

基于马尔可夫链的可信软件动态评估模型

软件可信度评估受主观经验、主观决策及有限理性的影响,评估结果的精确性和客观性无法得到全面保证。为了解决上述问题,本文利用马尔科夫连,以经典可信软件属性指标体系为基础,从软件层次属性的动态变化考虑提出了一种时间情境下的动态评估模型。通过模糊综合评判和层次分析法进行量化以确定子属性的权重和元属性的相对权重,应用马尔科夫过程构建各层级属性的内部定向转化概率模型,通过模糊算法得出最终的可信评估结果。结论表明,本文构建的模型,在一定程度上更加符合软件应用的实际情形,在逻辑上更具有说服力。实例也说明了本模型的科学性和有效性。     

英飞凌XMC4500控制的移相全桥ZVS DC/DC变换器

移相全桥变换器移相PWM信号的产生方式主要有模拟电路控制和数字电路控制两种.首先分析了数字控制与模拟控制对系统整体性能的影响;然后简要介绍了移相全桥DC/DC变换器PWM信号的特点,并提出了以XMC4500为基础的数字控制方案的硬件设计和双闭环控制流程;最后详细介绍了数字控制的具体实现过程,并通过样机试验证明了数字化控制的可行性.     

基于概率熵判据的大坝位移预警概型比较

基于数理统计原理,依据概率分布采用小概率估计方法拟定大坝位移预警指标是实现大坝安全监控的常用手段.借助系统可靠度分析方法,选取能够良好刻画系统服役性态的威布尔(Weibull)分布(三参数及二参数)、伽玛(Gamma)分布和对数正态(Log-normal)分布,针对大坝典型坝段位移监测序列,分别建立其概率分布模型,实现对分布参数的求解,再以最大熵原理为判据,选取能最客观描述大坝服役性态的分布,结合大坝失事概率,完成概率分布模型比较研究和位移预警值估计工作.实例表明:相较于其他分布,三参数Weibull分布能最客观描述典型坝段服役性态,故利用其对坝段位移预警值进行估计更加可靠.