排序方式: 共有22条查询结果,搜索用时 15 毫秒
1.
为研究羟丙基甲基纤维素(HPMC)在干法烟草薄片的应用价值,将其与3种常见胶粘剂(瓜尔胶、魔芋胶和羧甲基纤维素钠(CMC)进行对比,对不同胶粘剂体系的水溶液粘度测试、薄膜傅里叶红外光谱测试,胶粘剂及相应薄片的350℃低温热裂解分析和对应薄片抗张强度测试。结果表明:1wt%含量的HPMC水溶液10 min即可溶解,并可在烟草薄片的加工过程中调节涂布液粘度;HPMC与其他3种胶粘剂复配后存在氢键等物理交联作用,提高了对应胶粘剂制备的干法烟草薄片的纵向抗张强度,均>0.5 kN/m; 1wt%用量HPMC制备干法烟草薄片热裂解产物中有毒和刺激性物质含量低,分别为1.83%和5.31%。本文研究表明HPMC制备的干法烟草薄片综合性能较好,有较好应用价值。 相似文献
2.
3.
五种中药中微量元素及重金属元素的含量分析 总被引:3,自引:0,他引:3
用微波消解-原子吸收分光光度法对巴戟天、大黄、陈皮、板蓝根、茯苓等5种中药材中的7种金属微量元素进行了含量分析。结果表明,该法的线性良好,重现性在3.3%~11%之间,精密度在2.6%以内,回收率满足定量分析要求;5种药材中铅均未超标,茯苓中镉超出国家标准;5种药材里的铜含量均有超标,其中,巴戟天超标最严重;铁在5种药材中的含量最高,其中以巴戟天含量最为丰富,达到了746.750 mg/kg,其次是锌和锰,铬的含量最少。结论:对5种药材中铜均出现超标,虽然在边缘位置,但应该予以重视;巴戟天中丰富的铁元素,可能在防止癌变发生和发展中起到一定功效。 相似文献
4.
脉冲在时域二次折射率介质中的传播 总被引:3,自引:1,他引:2
从空域与时域的相似性出发,把克尔介质近似为时域二次折射率介质,从而得到了脉冲在该介质中的解析形式,并给出了相应的时域传输矩阵。 相似文献
5.
短脉冲高斯光束的时空形式 总被引:2,自引:0,他引:2
考虑到腔模光腰尺寸的频率依赖性,得到了一短脉冲高斯光束在自由空间传播的时域解析形式,发现其可由一复时间变量来描述,复时间变量的实部给出了脉冲的传输时间,其与波前曲率有关,虚部给出了空间量值,两者的交叉项称为时空耦合,并对傅里叶变换极限脉冲和啁啾脉冲的时空形式作了分析。 相似文献
6.
研究人员正在寻求突破飞秒界限的途径.文章简单评述了高次谐波产生阿秒脉冲的可能性、现实性、面临的障碍以及新的科学挑战. 相似文献
7.
Carrier shock and frequency conversion of a few—cycle pulse laser propagating in a non—resonant two—level atom medium 下载免费PDF全文
We have studied the spectral behaviour of few-cycle soliton pulses in a non-resonant two-level atom medium by solving the full Maxwell-Bloch equations. It is demonstrated further that the carrier effects play an important role in the propagation of the few-cycle pulse laser. When the frequency detuning is not very large, both the population distribution and the refractive index of the medium follow the oscillatory carrier field instantaneously; in this case, carrier-wave compression or carrier shock occurs, and a supercontinuum broader than that in the resonant medium may be generated. When the frequency detuning is large, the carrier shock is weak and the spectrum is not continuous, only showing an odd harmonic radiation. 相似文献
8.
9.
Reversible waveform conversion between microwave and optical fields in a hybrid opto-electromechanical system 下载免费PDF全文
Li-Guo Qin 《中国物理 B》2021,30(6):68502-068502
We present a scheme of reversible waveform conversion between microwave and optical fields in the hybrid opto-electromechanical system. As an intermediate interface, nanomechanical resonator optomechanically couples both optomechanical cavities in the optical and microwave frequency domains. We find the double-optomechanically induced transparency and achieve coherent signal waveform bi-directional transfer between microwave and optical fields based on quantum interference. In addition, we give an analytical expression of one-to-one correspondence between the microwave field and the optical output field, which intuitively shows the reversible waveform conversion relationship. In particular, by numerical simulations and approximate expression, we demonstrate the conversion effects of the three waveforms and discuss the bi-directional conversion efficiency and the bandwidth. such a hybrid opto- and electro-mechanical device has significant potential functions for electro-optic modulation and waveform conversion of quantum microwave-optical field in optical communications and further quantum networks. 相似文献
10.
The spectrum evolution of a few-cycle optical pulse in a resonant two-level atom medium is studied theoretically by using the full Maxwell--Bloch equations. On the propagating pulse, significantly much faster oscillation components separated with the main pulse appear due to strong self-phase modulation and pulse reshaping. In this case, ideal self-induced transparency cannot occur for a 2π pulse. The spectrum of the 4π pulse shows an evident oscillatory feature because of the continuum interference of the separate pulses. For larger pulse areas, continuum generation from near ultraviolet to infrared occurs. 相似文献