物理隔离技术的特点及应用

阐述了物理隔离技术的发展及特点,其中较为详细地描述了物理隔离设备在各个发展阶段的技术特征、现阶段物理隔离装置基本技术原理和技术优势、现阶段物理隔离装置在安全上的新要求,并对国内市场上现有主流产品性能进行了比较．以电力监控系统安全体系方案为例,分析了该方案在安全防护方面的思路和特点,并在此基础上,给出物理隔离装置在电力监控系统中的典型应用．     

Multiscale Simulation on the Influence of Dimethyl Hydantoin on Mechanical Properties of GAP/RDX Propellants

The influence of dimethyl hydantoin (DMH) on the mechanical properties of GAP/RDX propellant was studied by molecular dynamics (MD) and dissipative particle dynamics (DPD) simulation. The results showed that the binding energies (E_binding) between GAP and different surfaces of RDX were in the order of (010)>(001)>(100). Compared to GAP/RDX, GAP grafted with DMH (GAP‐DMH) exhibits higher binding energies with RDX, and the sequence of E_binding turns to (001)>(010)>(100). Radial distribution simulations demonstrated that GAP‐DMH is more close to the surfaces of RDX, increasing the van der Waals energies between GAP‐DMH and RDX. The stress and strain of GAP‐DMH/RDX excel those of GAP/RDX. DPD simulations showed that GAP‐DMH was able to restrain the agglomeration of RDX, to improve the dispersibility and to enlarge the contact surface with RDX, which also increased the mechanical properties of GAP/RDX propellant.     

Changes of the sensorial attributes of white wines with the application of new anti-mildew fungicides under critical agricultural practices

Although the winemaking process could allow the dissipation of residues of fungicides applied under critical agricultural practices (CAP), their residual levels could alter the biosynthesis of volatile compounds. The purpose of this work is to look for changes in the aroma profile of those wines in comparison with wines treated under good agricultural practices (GAP). Four new fungicides (mandipropamid, valifenalate, cyazofamid and famoxadone), used to control downy mildew (Plasmoparaviticola), were applied under CAP in an experimental vineyard producing white grapes (Vitisvinifera) of Godello var. Once grapes were harvested, single vinifications were performed. Possible modifications of sensorial properties of wines were evaluated by a trained sensorial testing panel constituted of 7 experts. The fungicide residues induced an increment of typical fermentative odours associated with esters in treated wines. The critically treated wine was moved to a sweeter balance with a ripe fruit taste, associated with higher viscosity and greater cloudiness.     

推行GAP管理是中国烟叶生产的必由之路

为使各级烟叶组织、管理和生产部门迅速认识世界发达国家采用的优质农业生产管理模式———GAP,推行GAP,全面快速提升中国烟叶生产技术和质量管理水平,使中国优质烟叶生产形成规模,走向世界,详细介绍了GAP的概念、在我国烟叶生产推行GAP的意义和实施措施,以及云南省陆良县烟草公司2003年推行GAP、建立烟叶质量追踪系统的实践经验。认为:①陆良县烟草公司推行GAP是成功的,其实施措施得当,工作细致,成效显著,从根本上改变了我国多年来陈旧的烟叶生产、管理、收购与质量监督模式,为提高我国烟叶生产质量及大规模进入国际市场开创了一条新的途径;②GAP是可行的、适合中国国情的、行之有效的优质烟叶生产与管理方法,是中国烟叶提高质量走向世界的必由之路!     

Network regulation and properties optimization of glycidyl azide polymer-based materials as a candidate of solid propellant binder via alternating the functionality of propargyl-terminated polyether

A kind of glycidyl azide polymer (GAP)-based composite has been fabricated using propargyl-terminated ethylene oxide-tetrahydrofuran copolymer (PPET) with two (p-) and three (t-) alkyne functionalities via Huisgen reaction. Independent upon the PPET functionality, both crosslink densities and mechanical properties for two GAP/PPET systems showed a positive-interrelation changes of initial increase and subsequent decrease with an increase of azide/alkyne molar ratios. At equivalent of azide/alkyne molar ratios, the composites containing t-PPET with higher alkyne functionality exhibited better mechanical properties, while those with two alkyne functionality presented lower glass transition. Under the regulation of alkyne functionality as 3 and azide/alkyne molar ratio as 3:1, the tensile strength, Young's modulus and breaking elongation could simultaneously reach the maximum values of 1.38 MPa, 4.07 MPa, and 122.5%, which was ascribed to optimal participation of azide/alkyne reaction into network construction. Overall, this study provides an additional optimization route for network-structured binders in solid propellant system. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48016.     

螺栓连接有限元模型的弹性接触研究

采用刚性梁单元模拟螺栓连接结构来进行有限元分析不能准确计算螺栓连接区域的应力。根据真实螺栓连接结构的特点和连接原理,提出了基于弹性接触的螺栓连接模型,该模型引入GAP单元定义了被连接件之间的弹性接触与摩擦条件,并用实验验证了该方法的有效性。     

GAP推进剂粘合剂固化体系力学性能的研究

在保证推进剂加工工艺性能和能量性能的前提下,通过化学共聚的方法,选用主链柔顺性较好、且在推进剂中可单独用作含能粘合剂的3,3-双(叠氮甲基)氧丁环/四氢呋喃的共聚物(BAMO/THF)来改善聚叠氮缩水甘油醚(GAP)交联网络结构,在此基础上再加入合适的扩链剂和交联剂,所得弹性体的力学性能有大幅度的提高。当固化参数R=1.3,m(GAP)∶m(BAMO/THF)=75∶25,以1,4-丁二醇(BDO)为扩链剂,异佛尔酮二异氰酸酯(IPDI)/多异氰酸酯(N100)为固化剂,胶片的拉伸强度可达到1.03MPa,断裂伸长率达到505.3%。     

Rap1GAP二聚体的形成对其在细胞内定位的影响

目的观察Rap1GAP二聚体的形成对其在细胞内定位的影响。方法对绿色荧光蛋白标记的Rap1GAP野生体编码第90和99位氨基酸的核苷酸进行定点突变,制备绿色荧光蛋白标记的Rap1GAP二聚体缺失突变体M90和M99。将Rap1GAP野生体及二聚体缺失突变体单独或者分别与活化型Gα共转染HEK293细胞,在荧光显微镜下观察野生体和二聚体缺失突变体在细胞内的分布情况。结果野生型Rap1GAP与二聚体缺失突变体Rap1GAP分别单独转染HEK293细胞时,野生型和突变体Rap1GAP均弥漫分布胞质内;当野生型与突变体Rap1GAP分别与活化型Gα共转染HEK293细胞时,野生型和突变体Rap1GAP均主要分布在细胞膜上。结论Rap1GAP二聚体的形成对其在细胞内的定位没有影响。     

我国中药材农药残留污染研究现状

综述了我国中药材农药残留污染现状及污染特点，进一步阐述了中药材中农药残留限量标准的研究，提出了解决中药材中农药残留超标的相应措施及合理建议。     

全球良好农业规范的变迁和发展

介绍了GlobalGAP的发展历程.以水果与蔬菜标准为例,对比了第二版与第三版之间的变化和差异.与第二版相比,第三版认证产品范围扩大,结构上更合理,内容更加丰富,方便用户开展认证.