白羽肉鸡疾病流行特点及对策措施

在白羽肉鸡的养殖过程中,经常发生疾病,准确分析白羽肉鸡疾病流行特点,采取有效对策措施,才能保证养鸡业的健康持续发展,本文为此做了一些工作,供读者参考。

浅析奶牛繁殖障碍性疾病的防治

随着养殖业的不断发展,在养殖过程中也会发生一些疾病困扰养殖户。常见的繁殖障碍性疾病是奶牛养殖中的比较常见的疾病,本文对其发病的临床表现进行分析并找到合理的防治方法,通过常见的几种繁殖障碍性疾病的发病情况处理,从而得到如何防止奶牛养殖过程中常见的繁殖障碍性疾病。

Numerical studies on pair production in ultra-intense laser interaction with a thin solid-foil

A theoretical and numerical model of photon and electron–positron pair production in strong-field quantum electrodynamics（QED） is described. Two processes are contained in our QED theoretical model, one is photon emission in the interaction of ultra-intense laser with relativistic electron（or positron）, and the other is pair production by a gamma-ray photon interacting with the laser field.This model has been included in a PIC/MCC simulation code named BUMBLEBEE 1 D, which is used to simulate the laser plasma interaction. Using this code, the evolutions of electron–positron pair and gamma-ray photon production in ultra-intense laser interaction with aluminum foil target are simulated and analyzed. The simulation results revealed that more positrons are moved in the opposite direction to the incident direction of the laser under the charge separation field.

基于三端口网络模型的折叠波导行波管注波互作用理论研究

将周期性慢波结构中的单元结构等效为一个三端口网络,利用高频结构模拟软件确定等效模型的参数,由此建立了一种通用的慢波结构等效模型.该方法不需要进行复杂的电路等效,直接由高频软件得到通道内场分布,因此较解析方法简单,又不像等效线路模型那么烦琐.基于该三端口网络模型,建立了适用于折叠波导行波管的一维注波互作用非线性理论模型,编写了数值计算程序,对一支折叠波导行波管进行了模拟.该理论模型模拟的结果与实验结果误差小于10%.该理论模型可以用于指导新型折叠波导行波管的设计及非线性模拟研究.