Effects of different carbon sources and C/N values on nonvolatile taste components of Pleurotus eryngii

Pleurotus eryngii, the second largest industrial cultivation mushroom in China, is usually cultivated on substrates mainly consisting of sawdust and corncob. In this study, experiments were performed to determine the effects of different carbon sources and C/N values on nonvolatile taste components of P. eryngii. The effects of different carbon sources on nonvolatile taste components levels revealed that sawdust was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while corncob was beneficial to high contents of carbohydrate, polysaccharides and trehalose. At the similar C/N values, relatively higher sawdust content was beneficial to umami amino acid production, while relatively higher corncob content was beneficial to high contents of carbohydrate, polysaccharides and mannitol. Higher C/N value was beneficial to high levels of crude protein, amino acids, 5′‐nucleotides and equivalent umami concentration, while lower C/N value was beneficial to high contents of carbohydrate, polysaccharides and trehalose. These results provided information for P. eryngii fruit body industrial cultivation to obtain specific nonvolatile taste components with high levels.     

车辆悬架用电磁执行器的建模与试验研究

应用电磁感应的基本原理,设计了一种新型的车辆主动悬架用电磁直线执行器,该执行器具有响应快,出力大和动行程大的特点。通过两种不同的建模手段,即有限元建模和集总元件动力学建模的电磁力仿真对比分析,两者基本吻合,表明了执行器模型的准确性。利用所建立的有限元模型,研究了执行器结构参数如气隙厚度和次级铜层厚度对电磁力的影响规律,并选取合理的参数进行执行器的样件试制。通过对加工后的样机模型进行电磁力响应的试验测试,并分别与有限元模型和集总元件动力学数学模型进行相应的比较,试验数据与仿真结果基本一致,进一步验证了模型的准确性。     

一种脉冲氦离子化检测器气相色谱仪计量性能的校准方法

对脉冲氦离子化检测器(Pulsed Discharge Helium Ionization Detector,PDHID)的校准是确保微量气体分析数据准确性的重要保证。针对微量气体PDHID校准方法难点问题,采用实验设计方法,选择合适标准物质与色谱条件进行试验。实验结果表明:氢气等气体可作为标准物质,该校准方法检测限:DPDHID<2.5<10-12g/s,扩展不确定度:U rel<5%,k=2,可开展对PDHID的校准。     

Simulation Method of Dynamic Characteristics of Turbine Flow Sensor

Computational Fluid Dynamics (CFD) simulation is one of the important methods to study the performance and in-fluencing factors of turbine flow sensors. According to the working characteristics of the turbine flow sensor, the passive simulation method based on the six degrees of freedom (6-DOF) model and dynamic mesh is proposed in this paper. The reliability of the simulation method is verified by steady-state experiments and unsteady-state experiments. The results show that the trend of meter factor with flow rate acquired from the simulation is close to the experimental results, and the deviation between the simulation result and the experiment result is low with a maximum deviation of 2.88%. In the unsteady simulation study, the impeller speed changes with the inlet velocity of the turbine flow sensor, which has a good follow-up. The passive simulation method can be used to predict the dynamic performance of the turbine flow sensor.     

Q390高强抗震钢板残余应力检测方法对比及分析

利用盲孔法、X-Ray法、中子衍射法和超声法对Q390高强抗震板及U形弯曲件进行残余应力检测,并对这4种方法测试得到的应力结果进行分析研究。结果表明,以上4种检测方法均要考虑其特定的检测应用范围,X-Ray法针对钢板表面下微米级深度的微米级晶格尺度范围局部点应力进行检测,中子衍射法可在毫米级尺度局部区域进行应力检测,盲孔法反映的是因毫米尺度钻孔导致的钢板表面孔周边的应力变化,超声法则可以通过连续扫描检测整个钢板残余应力的宏观分布变化。因此,对于工业钢板,超声法测试残余应力更加科学、合理、准确。同时,通过U形试样建立稳定的应力应变场,利用超声设备使用不同参考态对Q390高强抗震板弯曲件及退火弯曲件进行测试,结果表明,测试参考态的选取对应力测试结果影响很大,材料各向异性的影响对应力测试结果不可忽视。     

固相萃取净化-气相色谱-质谱法测定染料中7种指示性多氯联苯

本文建立了以固相萃取(SPE)前处理净化、结合气相色谱-质谱(GC-MS)测定染料中7种指示性多氯联苯的分析方法。该法将染料样品经溶剂萃取后,通过固相萃取(SPE)净化、浓缩,气相色谱-质谱采用选择离子监测模式(SIM)测定,以保留时间和特征离子定性,外标法定量。     

农药多残留分析中QuEchERS方法介绍

主要讨论在农药多残留分析中的一种简便、快速、安全、价格低廉的分析方法——QuEchERS法。该方法的主要步骤是用含1%醋酸的乙腈对样品进行浸提,再加入无水硫酸镁与醋酸钠振荡促使其分层,随后进行分散固相萃取,即将浸提液转移至含有PSA吸附剂、硫酸镁的离心管中,运用Teflon涂层离心管进行离心,取离心液至自动进样瓶用于GC/MS或LC/MS进行测定,并对其稳定性和可靠性进行了分析和评价。同时本方法也可根据可供选择的分析仪器种类、检测限、靶标农药的范围以及使用介质的差异进行适当调整。     

Efficient synthesis of benzophenone derivatives in Lewis acid ionic liquids

Benzophenone and its derivatives were prepared via Friedel–Crafts acylation reactions using ionic liquids (ILs) of BmimCl–FeCl₃, BmimCl–AlCl₃ and BmimCl–ZnCl₂ as dual catalyst–solvent. Among them, BmimCl–FeCl₃ showed much higher catalytic activity than that observed for the other two ILs, and in conventional organic solvents. In these reaction systems, good to excellent yields (up to 97%) of acylation products were obtained in a short reaction time. This method features high yield, a simple product isolation procedure, ILs reusability and reduced waste discharge, thus rendering this catalytic system both efficient and environmentally friendly.     

基于QEMU的外部总线仿真技术

综合嵌入式系统通过外部总线实现各个子系统之间的通信连接。为解决综合嵌入式系统的接口测试问题,采用系统虚拟机仿真综合嵌入式系统的连接方式,通过在虚拟机中创建外部总线仿真模块,配置仿真模块的连接,从而实现虚拟机之间的通信。提出一种基于以太网通信的外部总线仿真结构,以CAN总线仿真为例,在全系统虚拟机QEMU的内部总线上配置与注册外部总线设备,为读写总线设备数据的接口建立共享内存,组织总线协议报文。实验结果表明,通过网络收发报文,可实现总线仿真节点模块之间的数据交换,从而达到仿真总线的数据通信功能。