Comparative Immune Efficacy of Native Inactivated and Attenuated Vaccines for Porcine Reproductive and Respiratory Syndrome Virus over 2 Consecutive Years

Porcine reproductive and respiratory syndrome(PRRS) was first described in the United States in1987. This syndrome was characterized by abor-tion, premature farrowing, stillborn and mummi-fied pigs, as well as respiratory disease with chron-ic poor performance of nursing and weaned pigsand death. PRRS has been recognized worldwideand is considered to be an economically importantglobal disease since its emergence[1]. Several pro-tocols such as enhancing management, quarantine,disinfection, …     

丹东站驼峰自动集中微机控制系统

介绍了丹东站驼峰自动集中微机控制系统的构成、功能及采取的安全性措施。该系统实现了峰上调车进路、机车下峰进路、推峰路等联锁关系的全微机化及溜放过程中驼峰信号的自动控制。     

朗伯-比尔定律偏差分析

本文将影响因素进行分类,将物理、化学、数学综合起来分析,比较产生偏差的原因,得出引起偏差产生的原因：光传播过程引起的偏差；仪器测量时误差导致的偏离；由溶液本身化学反应引起的偏离。通过研究使我们进一步理解了朗伯—比尔定律偏离的影响因素,并有助于我们提高分光光度法的精密度。