Effects of Low-Power Microwave Fields on Seed Germination and Growth Rate

Experiments were conducted to investigate the effects of low power microwave radiation on germination and growth rate in seeds. In the present paper, the bioeffects of low power (non-thermal intensity) microwave modulated with 1 KHz square wave have been studied. Experiments were performed in X-band frequencies using klystron based microwave test bench. Microwave parameters like frequency, power, exposure time and power density were varied while irradiating seed samples to study their influence on germination. The seed samples used for the experiment included wheat (Triticum aestivum), bengal gram (Cicer arietinum), green gram (Vigna radiate) and moth bean (Vigna Aconitifolia). Seed germination %, plant height, root length and dry matter % (biomass %) were recorded and compared with control seeds. The effects of different treatments were found to be stimulating the germination and seedling vigour of plants especially in power and exposure time treatments while increase in frequency and power density has reduced the seed germination and seedling vigour. The effect also varied with the nature of seeds.

微波照射下岩石损伤的数值模拟研究

以黄铁矿和方解石组成的岩石颗粒为研究对象,利用离散元方法建立简单二相矿物平面模型,为更好地表现微波照射下微裂纹的萌生和发展规律,模型采用平行黏结模型,考虑了影响微波照射效果的主要因素:功率密度、照射时长、矿物颗粒大小及形状,分析了在微波照射下吸波矿物晶体边界破坏过程及破坏规律。

热力学参数对微波照射下不同矿物温度与应力分布影响的数值研究

微波技术在矿物分离以及辅助破岩方面具有良好应用前景,但岩石热力学参数对其作用效果影响如何,还不明确。基于此,以黄铁矿与方解石为研究对象,采用数值模拟的方法研究了热传导率和膨胀系数对微波照射后模型温度与应力分布规律。研究发现:(1)随着热传导率的增大,模型整体温度呈下降趋势,最大拉应力位置由模型边缘向接触部位转移;(2)随着方解石热膨胀系数的增大,黄铁矿从受压变成受拉状态,方解石从单一受拉变成拉压并存状态;(3)在达到同等应力水平情况下,微波功率密度越大,能源消耗越少。该研究对了解微波诱发岩石损伤的机理、在矿物分离以及褶皱岩层中的应用具有一定意义。

大强度微波短期辐照对兔甲状腺的影响

用大强度微波短期辐照兔，发现微波辐照对甲状腺功能的影响与功率密度有关，血清Ｔ４浓度的改变是反映微波影响的一个较敏感指标，１０ｍＷ／ｃｍ２组Ｔ４水平上升，２００ｍＷ／ｃｍ２组Ｔ４水平有所下降，实验前后Ｔ４的增值与功率密度呈负相关。甲状腺组织学改变不明显。肛温仅２００ｍＷ／ｃｍ２组明显升高，表明微波对甲状腺功能的抑制可能是全身热效应所致。