木薯发酵制备酒精后剩余残渣的综合利用

木薯发酵制备乙醇会产生大量以淀粉和纤维素为主要成分的残渣。经实验证明,在浓硫酸(60%)、浓硝酸和催化剂共同作用下,经水解-氧化-水解可成功地将木薯渣制备成草酸。实验确定了用木薯渣制备草酸的较优条件,测定了产品的熔点,分析了剩余残渣、废水,结果表明剩余残渣和废水不会对环境造成污染,既为草酸的生产提供了新思路,又为农产品的残渣综合利用找到途径,发展前景广阔。     

高压直流输电线路对通信明线影响的仿真研究

如何评价高压直流输电线路直流谐波对附近通信明线的影响,对确保通信线路正常、安全运行,以及直流输电工程的建设有着十分重要的意义.根据强电线路对弱电线路的耦合影响理论,高压直流输电线路对通信明线的影响分为危险影响和干扰影响两部分,本文介绍了高压直流输电线路对通信明线影响的原理及计算分类,以及目前国内主要的高压直流输电线路对通信明线影响的限值,并对不同参数变化下的静电感应电压和杂音电动势变化情况进行了仿真,得出了结论,为直流工程设计提供了一些参考.最后给出了具体模型进行了计算.     

基于贝叶斯估计的起重机械主梁的可靠性预测

针对起重机械主梁工作环境的复杂性和在相同工作环境下可靠性数据不足的问题,将贝叶斯估计方法和数据拟合相结合,以主梁的退化量作为性能参数,建立了起重机械主梁在工作环境下的可靠性预测模型;利用贝叶斯估计方法最大限度地将工作现场数据和历史试验数据相结合,及时更新主梁在工作环境下性能参数的分布函数,进而估计工作环境下不同时刻主梁的可靠度,最后采用最小二乘法估计主梁的可靠性函数.预测结果表明,起重机械主梁失效满足参数为(9.290,225.9)的2参数威布尔分布,得到为了满足主梁98％的可靠度要求,最小的维修间隔周期为149天.     

基于心理学的图像多分辨率统计特征提取

从采集的图像数据中提取特征,这是图像的模式识别中最重要的问题之一,解决的方法通常依赖于对具体应用的经验知识,对同样的任务,人的视觉系统却以一种普适的方法去完成.本文从人的心理学特性出发,导出信号特征的全局性质,然后讨论由局域信号构成总体特征的统计方法,进而借助于信号的Lebesgue积分表示与测不准原理提出一种普适性的特征表示方法MSR.实验结果表明,对图像信号MSR是适合于并行计算的有效逼近.     

振动功率流方法诊断梁的损伤

利用振动功率流方法对无限直梁在集中力作用下的损伤进行了诊断研究。损伤部位模拟为转动弹簧,利用断裂力学的有关理论得到其转动刚度。研究了梁在集中载荷作用下的弯曲波运动以及振动功率流的输入和传播,分析了振动功率流与破损位置及其特征尺寸的关系。首先从理论上研究了破损诊断的具体步骤,然后进行了实验研究,结果证明了理论分析的准确性和可靠性。     

Truly Concomitant and Independently Expressed Short‐ and Long‐Term Plasticity in a Bi2O2Se‐Based Three‐Terminal Memristor

Concomitance of diverse synaptic plasticity across different timescales produces complex cognitive processes. To achieve comparable cognitive complexity in memristive neuromorphic systems, devices that are capable of emulating short‐term (STP) and long‐term plasticity (LTP) concomitantly are essential. In existing memristors, however, STP and LTP can only be induced selectively because of the inability to be decoupled using different loci and mechanisms. In this work, the first demonstration of truly concomitant STP and LTP is reported in a three‐terminal memristor that uses independent physical phenomena to represent each form of plasticity. The emerging layered material Bi₂O₂Se is used for memristors for the first time, opening up the prospects for ultrathin, high‐speed, and low‐power neuromorphic devices. The concerted action of STP and LTP allows full‐range modulation of the transient synaptic efficacy, from depression to facilitation, by stimulus frequency or intensity, providing a versatile device platform for neuromorphic function implementation. A heuristic recurrent neural circuitry model is developed to simulate the intricate “sleep–wake cycle autoregulation” process, in which the concomitance of STP and LTP is posited as a key factor in enabling this neural homeostasis. This work sheds new light on the development of generic memristor platforms for highly dynamic neuromorphic computing.     

煤与PVC共热解固体产物在燃烧中氯的释放特性

通过实验研究了煤与PVC共热解固体产物燃烧时氯的释放特性,结果表明,氯的释放量（率）与燃烧温度、煤与PVC共热解的温度以及共热解时PVC的加入量有关．燃烧温度越高,氯的释放率越大,900℃燃烧时,氯的释放率都在94％以上;热解温度越高。在同一温度燃烧时,氯的释放率越低．400℃时焦中氯的最高释放率达99．86％,而1000℃时焦中氯的最高释放率为94．35％．     

Contribution of extracellular polymeric substances from Shewanella sp. HRCR-1 biofilms to U(VI) immobilization

The goal of this study was to quantify the contribution of extracellular polymeric substances (EPS) to U(VI) immobilization by Shewanella sp. HRCR-1. Through comparison of U(VI) immobilization using cells with bound EPS (bEPS) and cells with minimal EPS, we show that (i) bEPS from Shewanella sp. HRCR-1 biofilms contribute significantly to U(VI) immobilization, especially at low initial U(VI) concentrations, through both sorption and reduction; (ii) bEPS can be considered a functional extension of the cells for U(VI) immobilization and they likely play more important roles at lower initial U(VI) concentrations; and (iii) the U(VI) reduction efficiency is dependent upon the initial U(VI) concentration and decreases at lower concentrations. To quantify the relative contributions of sorption and reduction to U(VI) immobilization by EPS fractions, we isolated loosely associated EPS (laEPS) and bEPS from Shewanella sp. HRCR-1 biofilms grown in a hollow fiber membrane biofilm reactor and tested their reactivity with U(VI). We found that, when reduced, the isolated cell-free EPS fractions could reduce U(VI). Polysaccharides in the EPS likely contributed to U(VI) sorption and dominated the reactivity of laEPS, while redox active components (e.g., outer membrane c-type cytochromes), especially in bEPS, possibly facilitated U(VI) reduction.     

水分胁迫条件下葡萄生理生化反应研究进展

从水分胁迫对葡萄叶、根的形态及气孔行为、光合作用、呼吸作用、质膜透性、氮代谢、碳水化合物代谢、活性氧代谢、内源激素变化等生理生化方面的研究进行了综述,为全面研究葡萄抗旱机理及进一步制定抗旱措施奠定理论基础.