饲料防霉剂的性能和使用     

金惠平 《湖州师范学院学报》2001,(Z1)

着重介绍几种常见饲料防霉剂的霉抑制性、腐蚀性、挥发性、扩散性、离解性和相对功效，以及防霉剂的添加量及添加工艺．  相似文献   

对羧基苯偶氮硫代若丹宁固相萃取光度法测定烟草及其添加剂中的汞   总被引：1，自引：0，他引：1  

张莹  杨光宇  张承聪 《昭通师范高等专科学校学报》2005,27(2):24-28

研究了对羧基苯偶氮硫代若丹宁 (CPATR)与汞的显色反应,在pH为3.5的醋酸-醋酸钠缓冲介质中,吐温-80存在下, CPATR与汞反应生成2:1稳定络合物,该络合物可被Waters Sep-Pak C18小柱固相萃取,用氮-氮二甲基甲酰胺(DMF)洗脱后用光度法测定,在洗脱液介质中,λmax＝535 nm,体系摩尔吸光系数达8.70×103 m2/mol. 汞的质量浓度在0.05～4.0 mg/L内符合比尔定律. 该方法可用于烟草及其添加剂中汞含量的测定,结果满意.  相似文献   

Effect of Mixed Solvents and Additives on the Habit Modification of 6-APA Crystals     

龚俊波王静康  卫宏远 《天津大学学报(英文版)》2005,11(3):157-161

6-aminopenicillanic acid (6-APA) crystals obtained under different physical and chemical conditions of the solutions may present different habits. The habits of diamond-shaped plates are desirable compared with other habits of 6-APA crystals. To obtain ideal 6-APA crystals, the effects of the mixed solvents and additives on 6-APA crystal habits were investigated. Ethanol or acetone was used as the organic solvent, and impurities existing in the ,6-APA purification process were used as the additives. 6-APA growth habits were changed when the concentrations of ethanol, acetone or phenyl acetic acid were increased to exceed their critical concentration. The observed results show that the dominant face on 6-APA crystals was identified to be , {020}, but the overall habit was controlled by the relative growth rates of the : 101 and {002} faces. Crystal growth rates and habits can be appreciably changed by specific adsorption of additives on crystal faces. In some cases solvent molecules can act in a similar way and may be regarded as bulk additives. The effects of additives and organic solvents on 6-APA crystal habits were the results of adsorption effect,which fitted the experimental results quite well.  相似文献   

叠压给水设备二级串联加压供水问题对策     

冯家敏 《中国科技信息》2014,(9):223-225

针对某依山而建的住宅楼盘,二期工程建设时方案进行了较大的调整,使得与一期工程同时交付使用的叠压给水设备的扬程和流量都不能满足住宅小区用水需求的问题,采用了在二期工程内增设一套叠压给水设备,通过两套设备二级串联接力加压供水的方法来满足二期住户的用水需求,为了实现两套设备协调运行和弥补第一套设备供水量的不足,对第二套设备系统配置进行了优化设计。运行效果良好。  相似文献   

引入租赁的报童模型在加性需求下的一个基本结果     

杨明霞  史存琴  付桐林 《咸阳师范专科学校学报》2014,(6):11-13

在引入租赁的报童模型及其利润函数的基础上,给出了加性需求下引入租赁的报童模型的平均利润函数和一个基本定理,并通过算例进行了验证。  相似文献   

开式齿轮润滑脂的工业生产研制     

马文全  赵俊 《兰州石化职业技术学院学报》2010,10(3):15-17

开式齿轮多为大型设备,齿轮传动比较大,小齿轮使用较为频繁,并且设备服役时间要求超过10-30年,因此对润滑要求比较苛刻。为满足客户要求,针对重负荷开式齿轮运行工况对润滑脂性的特殊要求,结合生产工艺,选择合适的稠化剂与功能添加剂,重点考察了添加剂的配伍性,开发研制出开式齿轮润滑脂,以满足特殊工况需求。  相似文献   

Modeling Nonlinear Structural Equation Models: A Comparison of the Two-Stage Generalized Additive Models and the Finite Mixture Structural Equation Model     

W. Holmes Finch 《Structural equation modeling》2013,20(1):60-75

Researchers have devoted some time and effort to developing methods for fitting nonlinear relationships among latent variables. In particular, most of these have focused on correctly modeling interactions between 2 exogenous latent variables, and quadratic relationships between exogenous and endogenous variables. All of these approaches require prespecification of the nonlinearity by the researcher, and are limited to fairly simple nonlinear relationships. Other work has been done using mixture structural equation models (SEMM) in an attempt to fit more complex nonlinear relationships. This study expands on this earlier work by introducing the 2-stage generalized additive model (2SGAM) approach for fitting regression splines in the context of structural equation models. The model is first described and then investigated through the use of simulated data, in which it was compared with the SEMM approach. Results demonstrate that the 2SGAM is an effective tool for fitting a variety of nonlinear relationships between latent variables, and can be easily and accurately extended to models including multiple latent variables. Implications of these results are discussed.  相似文献   

"不但p,更q"复句语义探究     

沈红丹 《连云港师范高等专科学校学报》2006,(1):42-44

对于所发现的“不但p,更q”复句的问题,运用对比分析的方法,探究了此类句式的深层语义。  相似文献   

石斑木果皮红色素稳定性的影响因子     

黄晓昆  黄晓冬  苏志华 《泉州师范学院学报》2008,26(2):110-115

实验研究石斑木果皮红色素的理化性质和光、温度、金属离子、食品添加剂等对色素稳定性的影响．结果表明：该色素在80℃以下较稳定;日光照射,金属离子K^＋、Na^＋、Mg^2＋、Ca^2＋、Cu^2＋、Mn^2＋、Fd^3＋等对色素液的吸光度有明显的不良影响;高浓度VitC和柠檬酸对色素降色明显;蔗糖和苯甲酸钠对色素无较大影响．  相似文献   

大学生英语写作中连接衔接特征的实证研究     

张燕 《四川教育学院学报》2008,24(9):80-82

基于Halliday的语篇衔接理论,对197名河南科技大学非英语专业大二学生的四级模拟作文中的好作文和次作文就连接衔接特点进行了抽样统计分析。结果表明,好作文和次作文中增补连接和因果连接的使用频率存在显著差异,好作文中的增补连接词和因果连接词的使用更为丰富多样。两类作文中转折型连接词的使用频率都较高,但词汇使用单一,主要是but和however,但是两类作文中都存在着时间型连接词过少使用的情况。  相似文献