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1.
建立了固相萃取/高效液相色谱(SPE/HPLC)测定化妆品中5种抗组胺药物(多西拉敏、曲吡那敏、溴苯那敏、苯海拉明、氯苯沙明)残留的分析方法。试样经三氯乙酸溶液超声提取,PCX柱净化后,以甲醇-磷酸盐缓冲溶液为流动相,经C18柱分离后进行HPLC检测。5种抗组胺药物在5.0~100 mg/L范围内均呈良好的线性关系,线性系数均大于0.999。在5.0、10.0、25.0 mg/kg 3个加标水平下的平均回收率为92%~108%,相对标准偏差(RSD,n=6)为2.1%~4.2%,检出限为0.5~1.0 mg/L。该方法灵敏度高、重现性好、定量准确。  相似文献   
2.
本文阐述了噪声的基本特性和类型,并根据噪声的基本理论详细地分析和计算了一种变送器电路中的噪声。其中主要包括1/f噪声是如何引起的,计算出了其值的大小,并利用HSPICE仿真工具加以验证。在此基础上提出了通过降低输出电阻和采用跨导放大器的电路结构来降低噪声,最终实现了电路的噪声优化。  相似文献   
3.
本文以一种低噪声放大器为例,着重分析了电路的热噪声特性,结合理论分析计算了低噪声放大器的热噪声,利用HSPICE仿真软件对电路的热噪声进行仿真,与理论计算所得的热噪声比较。按照本设计采用的低噪声放大器的结构特点,对电路进行了优化,有效地减小了电路产生的热噪声。  相似文献   
4.
建立了固相萃取-超快速液相色谱-串联质谱法(SPE-RRLC-MS/MS)同时测定化妆品中9种抗过敏药物残留(多西拉敏、美沙吡林、曲吡那敏、溴苯那敏、苯海拉明、赛克利嗪、二苯拉林、羟嗪和氯苯沙明)的方法。试样经三氯乙酸溶液超声提取、离心、Plexa PCX柱净化后,以甲醇-0.1%甲酸溶液(含5 mmol/L甲酸铵)为流动相,用RRLC进行分离。在电喷雾正离子模式下,以选择反应监测(SRM)方式采集数据进行定性与定量分析。9种药物在1.0~50.0!g/L范围内均呈良好的线性关系,相关系数均大于0.99;在2.0,5.0和20.0!g/kg3个浓度加标水平下的平均回收率为90.6%~103.5%;相对标准偏差(RSD,n=6)为2.5%~6.0%;检出限为0.3~0.6!g/kg,定量限为1.0~2.0!g/kg。  相似文献   
5.
In this paper, we investigate the optical transmission properties of perfect and defective two-segment-connected tri- angular waveguide networks (2SCTWNs) and find that after introducing defects in networks, many groups of transparent extreme narrow photonic passbands (ENPPs) will be created in the middle of the transmission spectra, the number for each group and the group number of ENPPs can he adjusted by the matching ratios of waveguide length (MRWLs), the number of defects, and the number of unit cells of 2SCTWNs. The influences of MRWL, number of defects, and number of unit cells on the number, width, and position of these ENPPs are researched and a series of quantitative rules and prop- erties are obtained. It may be useful for the designing of high-sensitive optical switches, wavelength division multiplexers, extreme-narrowband filters, and other correlative waveguide network devices.  相似文献   
6.
We have systematically investigated the structures, morphologies, microwave surface resistance, DC performances and the substrate qualities of three YBa2Cu3O7-x(YBCO) thin films 30mm in diameter. The three samples deposited by the same process have been proved of different properties. It has been shown that the structure and superconducting properties of the thin film depend strongly on the quality of substrate.  相似文献   
7.
魏威  卢剑 《移动通信》1998,22(3):28-31
本文从网络结构和分层协议模型两个方面对移动交换机(MSC)进行了功能分析。MSC工程设计的基本思路是基于现有的数字有线交换机。最后介绍Ericsson AXE10移动交换机的设计思想。  相似文献   
8.
In this paper, by means of the network equation and generalized dimensionless Floquet-Bloch theorem, we study the influences of the number of connected waveguide segments (NCWS) between adjacent nodes and the matching ratio of waveguide length (MRWL) on the photonic bands generated by quadrangular multiconnected networks (QMNs), and obtain a series of formulae. It is found that multicombining networks (MCNs) and repetitive combining networks (RCNs) are equivalent to each other and they can all be simplified into the simplest fundamental combining systems. It would be useful for adjusting the number, widths, and positions of photonic bands, and would possess potential applications for the designing of all-optical devices and photonic network devices.  相似文献   
9.
本文采用实验方法对高 T_c 超导材料 YBa_2Cu_3O_(7-6)块材的微波表面特性进行了研究,探讨了材料制备的工艺参数同微波性能的关系;还采用单腔多模和部分置换的方法,在 2cm 和3cm 频段,成功地测试和计算了高 T_c 超导材料 YBa2Cu_3O_(7-6)块材样品,在77K 时微波表面阻抗同工作频率的关系.其方法简单,测试准确,重复性好,对进一步研究高温超导体在微波频率下的表面物理特征有重要意义.  相似文献   
10.
We have systematically investigated the structures, morphologies, microwave surface resistance, DC performances and the substrate qualities of three YBa2Cu3O7-x(YBCO) thin films 30mm in diameter. The three samples deposited by the same process have been proved of different properties. It has been shown that the structure and superconducting properties of the thin film depend strongly on the quality of substrate.  相似文献   
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