中红外光谱法对肉苁蓉的定性和半定量分析

本文尝试将中红外光谱(MIR)应用于肉苁蓉药材的质量评价和分析中.首先比较肉苁蓉药材粉末样品及其3种主要活性成分提取物,包括本乙醇总苷(PeGs)、甘露醇(Man)和多糖的红外光谱图差异,得出3种提取物的特征红外吸收峰,确定药材样品各特征峰的强弱与PeGs和Man含量高低的关系.然后用Spectrum v5.02软件计算得出不同波段内药材图谱与两种提取物图谱的红外相似系数,通过SPSS11.0软件分析发现,药材PeGs的含量(y)和1800~1200cm-1范围内的红外相似系数(x)呈极显著相关(R2=0.9927),回归方程:y=19.846x+0.0623.同样,药材Man的含量(y)与1100~600cm-1波数范围的红外相似系数(x)呈极显著相关(R2=0.9705),回归方程:y=13.855x-0.1714.因此,M IR可作为肉苁蓉药材质量定性和半定量分析的快速有效方法,直观评价药材质量.     

重掺硅中氧的测定

研究了重掺硅中氧的测定,实验首先选用轻掺(ρ＞10Ω@cm)样品分别用气体熔化分析法(GFA法)和傅里叶变换红外法(FTIR法)测氧,而后用GFA法测定了重掺锑、砷、硼单晶的氧浓度.实验发现用GFA法和FTIR法测氧,二者的结果成很好的线性关系,为便于比较可将重掺硅在GFA法下的测定结果转换为FTIR法下的测定结果,还对影响GFA法测定结果的样品制取、样品处理、测试参数选择等方面进行了探讨.     

重掺硅中氧的测定

研究了重掺硅中氧的测定 ,实验首先选用轻掺 (ρ>10Ω· cm)样品分别用气体熔化分析法 (GFA法 )和傅里叶变换红外法 (FTIR法 )测氧 ,而后用 GFA法测定了重掺锑、砷、硼单晶的氧浓度 .实验发现用 GFA法和 FTIR法测氧 ,二者的结果成很好的线性关系 ,为便于比较可将重掺硅在 GFA法下的测定结果转换为 FTIR法下的测定结果 ,还对影响 GFA法测定结果的样品制取、样品处理、测试参数选择等方面进行了探讨     

碳对Si_(1-x-y)Ge_xC_y合金氧化的影响

利用椭圆偏振仪 (EL)、傅里叶红外光谱 (FTIR)研究了 Si1 - x- y Gex Cy 合金分别在 90 0℃和 10 0 0℃干氧气氛下形成氧化物的生长动力学 .结果表明 :在 90 0℃氧化时 ,随着合金中的替代碳含量的增加 ,氧化速率逐渐下降 ;而在 10 0 0℃下氧化超过 10 min后 ,Si1 - x- y Gex Cy 合金的氧化基本上与碳的含量无关 ,与 Si1 - x Gex 的行为一致 .这主要是由于在 10 0 0℃比较长时间的氧化过程中 ,替代位的碳逐渐析出形成 β- Si C沉淀 ,失去了对氧化过程的影响作用 .研究表明对于 Si1 - x- y Gex Cy 薄膜和器件的应用来说 ,氧化的温度必须要小于 10 0 0℃ .     

MOVPE生长Hg1-xCdxTe薄膜的实验研究

采用金属有机化合物汽相外延法(MOVPE)和多层膜互扩散生长工艺(IMP)在不同的生长条件下生长了许多Hg1-xCdxTe/GaAs(211)薄膜样品,并对样品进行了傅利叶红外透射(FTIR)和范德堡Hall测量;通过对许多实验数据进行系统的对比分析,总结了薄膜的生长规律,并对这些生长规律作出了理论分析,阐释了薄膜的微观生长机制.     

盐酸苯海拉明缓释片的制备

目的 ：制备24h缓释的盐酸苯海拉明缓释片。方法 ：建立盐酸苯海拉明紫外分光光度法的含量测定方法 ;以片剂成型情况确定制备工艺;以释放度为评价指标,筛选盐酸苯海拉明缓释片的骨架材料,确定处方;根据优选的处方工艺制备盐酸苯海拉明缓释片,考察其质量。结果 ：紫外分光光度法：在纯化水中的标准曲线：y=0.0015x+0.015,r=0.9998,线性范围：130.5～451.7μg/mL;在模拟胃液中的标准曲线：y=0.0016x-0.0074,r=0.9993,线性范围：130.5～401.5μg/mL;在模拟小肠液中的标准曲线：y=0.0016x-0.0041,r=0.9991,线性范围：130.4～401.5μg/mL;在模拟结肠液中的标准曲线：y=0.0016x-0.0179,r=0.9991,线性范围：150.5～401.5μg/mL。精密度和回收率符合规定。优选的处方工艺为：盐酸苯海拉明75mg、乙基纤维素360mg、滑石粉15mg,粉末直接压片,压力70N。通过优选的处方及制备工艺制备的盐酸苯海拉明缓释片,片剂表面光滑整洁,片重差异及在不同释放介质中的释放度均在80%以上。结论...     

红外光谱在翡翠研究中的应用

应用紫外一可见一近红外光吸收谱法和傅立叶红外粉末透射光谱法对翡翠进行了分析.分析结果发现:翡翠存在一些特征吸收峰;不同特征的翡翠其吸收峰亦有差异,这些差异为翡翠的研究提供了有用的信息.     

Dy3+和Eu3+共掺NaY(MoO4)2荧光粉合成与发光性能研究

用高温固相法制备了一系列2 at.%Dy³⁺和x at.%Eu³⁺(x=0,0.1,0.5,1,2,5)共掺NaY(MoO₄)₂样品。X射线衍射(XRD)、扫描电子显微镜(SEM)及红外光谱(FTIR)表征结果表明所合成的样品为四方相结构,空间群为I4₁/a。进一步研究了样品的激发光谱和在近紫外光激发下的发射特性,结果表明Dy³⁺和Eu³⁺之间存在能量共振传递,从而增强了Eu³⁺的发光。2 at.%Dy³⁺和2 at.%Eu³⁺共掺样品的CIE色度坐标值(x=0.659,y=0.338)接近NTSC规定的标准值,因而有望作为显色性能优良的发光材料用于固态照明领域。此外，NaY(MoO₄)₂物化性能稳定,易采用提拉法生长,因此本研究结果可以为Dy³⁺和Eu³⁺共掺NaY(MoO     

MOVPE生长Hg1—xdCdxdTe薄膜的实验研究

采用金属有机化合物汽相外延法（MOVPE）和多层膜互扩散生长工艺（IMP）在不同的生长条件下生长了许多Hg1-xCdxTe/GaAs(211）薄膜样品，并对样品进行了傅利红外透射（FTIR）和范德堡Hall测量，通过对许多实验数据进行系统的对比分析，总结了薄膜的生长规律，并对这些生长规律作出了理论分析，阐释了薄膜的微观生长机制。     

MBa_2Cu_3O_(7-δ)(M=Y,Sm,Gd,Eu)超导体的红外光谱

测定了多晶超导体MBa_2Cu_3O_(7-δ)(M=Y,Sm,Gd,Eu)的反射光谱和透射光谱。在远红外(40～360cm~(-1))反射谱中观察到5个特征反射峰和3个反转结构,在中红外反射谱中有一580cm~(-1)峰,在中红外吸收谱中有580～590cm~(-1)和615～627cm~(-1)两个峰。本文分析了这些峰对应的振动模,并由反转结构确定了超导能隙和比值γ=2Δ/k_BT_c。     

Emission infrared spectroscopy for in situ analysis of the OMVPE growth surface

Fourier transform infrared (FTIR) spectroscopy has proven to be an effective tool for the analysis of OMVPE growth. Both transmission and attenuated total reflection (ATR) provide information including identification and the relative concentrations of both reactants and products. Until recently we have only been able to apply transmission to the gas phase and ATR to in situ surface analysis. OMVPE is a heterogeneous process and ATR using a GaAs element is limited to temperatures where the sample is transparent,i.e. <400° C. Surface reactions are important to the overall process. We have recently developed a technique which effectively monitors the surface species in situ. All materials emit infrared radiation proportional toT ⁴. Under OMVPE growth conditions (400-70° C) this emission is considerable, particularly from the surface of the emitting sample. Emission spectra correspond directly to that of absorption spectra and can easily be collected with an FTIR spectrometer. The spectra yield the same information as transmission FTIR primarily for surface species. We have used this system to monitor the adsorption and reaction of TMGa and ammonia. We have identified adsorbed ammonia and TMGa on the surface and have been able to see how these molecules change as they decompose on the surface.     

Segmentation of intravascular ultrasound images: a knowledge-based approach

Intravascular ultrasound imaging of coronary arteries provides important information about coronary lumen, wall, and plaque characteristics. Quantitative studies of coronary atherosclerosis using intravascular ultrasound and manual identification of wall and plaque borders are limited by the need for observers with substantial experience and the tedious nature of manual border detection. We have developed a method for segmentation of intravascular ultrasound images that identifies the internal and external elastic laminae and the plaque-lumen interface. The border detection algorithm was evaluated in a set of 38 intravascular ultrasound images acquired from fresh cadaveric hearts using a 30 MHz imaging catheter. To assess the performance of our border detection method we compared five quantitative measures of arterial anatomy derived from computer-detected borders with measures derived from borders manually defined by expert observers. Computer-detected and observer-defined lumen areas correlated very well (r=0.96, y=1.02x+0.52), as did plaque areas (r=0.95, y=1.07x-0.48), and percent area stenosis (r=0.93, y=0.99x-1.34.) Computer-derived segmental plaque thickness measurements were highly accurate. Our knowledge-based intravascular ultrasound segmentation method shows substantial promise for the quantitative analysis of in vivo intravascular ultrasound image data.     

采用中红外空芯光纤探头的特征谱遥测系统

设计制作了多种空芯光纤探头,搭建了基于傅里叶变换红外光谱仪的遥测系统.实验结果表明,采用锥形耦合光纤为接收光纤的探头具有17.6%的高效系统传输效率.对聚碳酸酯、聚偏二氟乙烯等有机物和无水乙醇、甲苯等有机溶剂薄膜的光谱进行测量,得到了遥测光谱.根据甲苯在1605 cm-1波数的特征峰对甲苯/乙醇混合溶液中的甲苯浓度进行定量遥测分析.配置浓度在5%~50%的多份混合溶液用于建立定量模型,并独立检验.结果显示检验的预测均方根误差(RMSEP)为3.356,参考值和预测值的相关系数为0.9200.初步实现了对薄膜、混合溶液等进行红外特征谱的遥测.     

红外光谱法对聚烯烃中抗氧剂1010的定性、定量研究

本文介绍了用红外光谱法定性、定量测定聚乙烯、聚丙烯中抗氧剂1010的情况。分析了抗氧剂1010和PE、PP粉料的FTIR图,确定了抗氧剂1010在聚烯烃中的特征吸收峰(1746cm-1),详细分析了用抗氧剂1010分别与定量的PE、PP所制样品对所测谱图和所制曲线的影响。根据抗氧剂1010的标准曲线可知,抗氧剂1010的含量与其特征峰的吸收强度呈良好的线性关系,相关系数达0．98以上,回收率最低为90．0％。该研究可以对聚乙烯、聚丙烯中的抗氧剂1010进行定性及定量,对分析抗氧剂在聚烯烃中的影响和改性有着重要的实际意义。     

旋转对称性对红外超材料完美吸收器特性的影响

研究了超材料完美吸收器的旋转对称性对其吸收特性的影响.吸收器由金属颗粒/电介质/金属薄膜三层结构组成.以最上层是方形金属块为例,并通过在其y方向不同边沿处引入空气孔研究了四重、二重和非旋转对称吸收器的吸收特性.理论结果表明,当入射光偏振平行于x轴或y轴时,四重旋转对称结构有一个完全相同的吸收峰;二重旋转对称结构吸收峰会在入射光偏振平行于x轴时劈裂成两个峰;而无论入射光偏振平行于x轴或y轴,非旋转对称结构的吸收峰都会劈裂成两个峰.不同重数旋转对称性对吸收峰特性影响的结果将有助于设计新型的偏振无关的吸收器.     

基于偏振复用技术的光频梳研究

为提高光频梳带宽和谱线平坦度,设计了一种基于偏振复用和电吸收调制(EAM)技术的光频梳产生方案。通过调整EAM参数产生除中心载波外的高平坦度光频梳,再结合偏振复用技术优化中心载波峰值功率,使得光频梳带宽整体提升一倍。文中讨论了相关参数对光频梳平坦度的影响,利用Optisystem软件搭建了基于该方案的微波频率可调载波重用全双工光载无线系统(RoF)。研究结果表明,在下行链路中当误码率为10^-9时,传输10 km与背靠背传输相比功率代价仅为0.42 dB。     

9.5 GHz GaInP/GaAs HBT divide-by-two frequency divider using super-dynamic D-type flip?flop technique

A frequency divider with super-dynamic D-type flip-flop is demonstrated in 2 mum GalnP/GaAs HBT (f_T = 40 GHz) technology. By biasing the HBT devices around tire peak transit-time frequency (f_T), the operating frequency of a D-FF with ECNFP (emitter-coupled negative feedback pairs) can be improved. At a supply voltage of 5 y a divide-by-two function of 9.5 GHz is achieved.     

TR-UWB系统性能分析与仿真

分析比较了3种基于自相关接收原理的超宽带发送参考（TR）冲击无线电系统,即简单TR（STR）系统、平均TR（ATR）系统和差分TR（DTR）系统在多径信道中的误码率（BER）性能、实现复杂度和传输速率,并对这3种系统的性能在CM1和CM2信道中进行了计算机仿真。分析和仿真结果表明,ATR和DTR的性能恒优于STR,但ATR和DTR的性能的优劣则取决于具体的参数取值,在一定的参数条件和复杂度约束下,DTR系统是一种在性能、复杂度和传输速率方面都能兼顾的比较折中的传输方案。     

Computer simulation of the human-body effects on acircular-loop-wire antenna for radio-pager communications at 152, 280,and 400 MHz

This paper presents an extensive computer simulation of the influence of the human body on a circular-loop-wire antenna to simulate the pager antenna. The coupled integral equations (CIEs) approach and the method of moments (MoM) are employed for numerical simulation of this antenna-body-coupling problem. The magnetic frill source is used to model the antenna-feeding structure. A realistically shaped full-scale human-body model (1.7 m) is constructed. A small loop antenna (loop radius b=1.7 cm and wire radius a=0.072 cm) of x, y, and z orientation, in free space or proximate to the human body at the top pocket (chest position) or belt level (waist position), is considered. Numerical results of the antenna characteristics and body absorption at 152, 280, and 400 MHz are presented and discussed for radio-paging applications. At 280 MHz, it is found that the real part of the impedance increases about five to ten times, and, hence, the antenna ohmic-loss radiation efficiency increases from 17% (in free space) to 69%, 44.3%, and 58.4%, respectively, for the x-, y-, and z-oriented loops when proximate to the body. The radiation efficiencies, reduced by the body-absorption effect, are 5%, 61%, and 25% for the x-, y-, and z-oriented loops, respectively. For the y-oriented loop, which is found to be the most suitable for paging communications, the antenna efficiencies are almost the same at the two location levels for all frequencies considered. The computed antenna characteristics influenced by the human body; including the input impedance, antenna patterns, cross-polarization field level, radiation efficiencies, and maximum and minimum power gains, are important for the antenna/RF design and the link-budget consideration