肺癌组织的红外光谱研究

应用傅里叶变换红外光谱法对肺癌及癌旁正常组织粉末样品进行了分析,结果表明, 肺癌组织和癌旁正常组织的红外光谱表现出较大的差异性: N2H峰在肺癌组织中向低波数频移, 1536cm- 1处蛋白质酰胺Ⅱ带与1169cm- 1处蛋白质分子C2OH伸缩振动谱带在肺癌组织中向高波数频移; CH2 和CH3 的相对强度比值I2854 / I2872及I2929 / I2959在正常组织中的比值要比肺癌组织中的比值明显减小;肺癌组织中核酸分子磷酸二脂基团PO2- 的对称伸缩振动的相对吸收强度明显增强;正常组织中脂类分子弯曲振动谱带吸收峰相对强度明显强于甲基变角振动谱带的相对强度,而在肺癌组织中这两处吸收峰的相对强度大小基本相等。说明傅里叶变换红外光谱法可用于对良、恶性肺部组织进行鉴别诊断,有希望发展成为肺癌快速诊断的一种新方法。     

人早幼粒白血病细胞裸鼠异种移植模型的傅里叶变换红外光谱探索

应用傅里叶变换红外光谱法对HL-60(人早幼粒白血病细胞)裸鼠异种移植模型癌变及癌旁正常组织粉末样品进行了分析研究.结果表明:(1)甲基CH3和蛋白质分子C-O峰在癌变组织中均有不同程度的频移,(2)正常组织的红外光谱在1746 cm-1处存在较强的吸收峰,而在肿瘤中只有较弱的吸收峰或观察不到吸收峰,(3)癌变组织核酸分子磷酸二脂基团PO2-的对称伸缩振动的相对吸收强度明显增强,(4)正常组织中脂类分子弯曲振动谱带吸收峰相对强度明显强于甲基变角振动谱带的相对强度,而在癌变组织中这两处吸收峰的相对强度大小基本相等.说明傅里叶变换红外光谱法可以用于对裸鼠癌变组织进行鉴别诊断,利用动物异种移植模型进行红外光谱分析可成为肿瘤红外光谱研究的一种新方法.     

天空背景近红外氧气A带光谱测量与分析

为研究被动测距技术中天空背景近红外氧气A带光谱特性,利用高光谱成像光谱仪,对不同天顶角下的天空近红外氧气A带光谱进行测量,并依据被动测距原理,计算出不同天顶角下的天空背景光谱的氧气吸收率。测量结果表明:天空背景光谱在氧气A带中有明显的特征吸收谱线存在,并且天顶角越大天空光谱氧气A带吸收强度越强,氧气吸收率越大。这为后续被动测距的背景抑制和目标光谱准确提取奠定了基础。     

^127I2在532nm波段谱线的理论计算

报道了计算^127I2B-X跃迁谱线频率及谱线的超精细分裂的频率间隔的经验方法。利用该方法，计算了532nm附近的^127I2吸收谱线的频率、波长及相对强度，同时确定了各谱线的振转跃迁。计算结果与实际观测很好地吻合，并预言了532nm附近^127I2的激发态跃迁吸收谱线。对已观察到的3条谱线的超精细分裂的频率间隔进行理论计算，简要总结了其分布规律。     

碱金属蒸气灯的光谱辐射特性

测量了碱金属蒸气灯的相对光谱分布,观察了碱金属蒸气灯的相对有效辐射效率、共振线自吸收后的光谱峰值间隔、红蓝翼谱带半极大值全宽与输入灯内功率的关系。     

晶体光谱特性

测量了0.8 at.-% Nd3+:Y0.5Gd0.5VO4的吸收光谱和荧光发射谱,光谱显示该晶体在808.5 nm有很强的偏振光吸收峰,且π偏振光(E∥C)吸收远强于σ偏振光(E⊥C)吸收,半高宽度分别为4.5 nm和12 nm,吸收截面分别为19.69×10-20 cm2和6.41×10-20 cm2;其荧光发射( 4F3/2→ 4I11/2跃迁)峰值波长在1064 nm,半高宽度为3.7 nm; 4F3/2→ 4I11/2跃迁的荧光寿命为110 μs;光谱特性表明Nd3+:Y0.5Gd0.5VO4晶体是潜在的高效率激光晶体材料.     

X射线照射HEp-2细胞的FTIR光谱研究

通过对不同剂量X射线照射的人上皮样喉癌细胞(HEp-2)的傅里叶变换红外(FTIR)光谱研究发现:不同剂量组HEp-2细胞受到的影响存在较大差异.与对照组相比,HEp-2细胞内部的蛋白质、核酸和脂类的含量在较大剂量组大幅减少;随照射剂量的逐渐增大,部分谱线位置频移较明显,如3314cm-1谱线逐渐红移3～16 cm-1,1454cm-1谱线逐渐蓝移3cm-1,1400cm-1谱线逐渐红移3cm-1,2847cm-1谱线逐渐蓝移4～8 cm-1,表明这些谱线对应的基团内部构象发生变化.另外,从相对峰强比I1654/I1542,I1454/I1400,I2958/I2847随照射剂量的变化关系发现,同对照组相比,HEp-2细胞在8Gy组内部蛋白质、核酸、脂类的含量和构象改变最为明显,癌化程度最弱,说明在所设定剂量组中8Gy X射线照射对HEp-2细胞的影响相对最好,这忖为将来进一步寻找射线作用于癌细胞的最佳剂量提供了一定的实验依据.     

病害烟叶的傅里叶变换红外光谱研究

利用傅里叶变换红外光谱法研究了正常烟叶和四种病害烟叶,结果显示,它们的红外光谱主要由蛋白质、脂类化合物及多糖的振动吸收谱带组成。烟叶光谱整体相似,仅在1800～750 cm-1范围,正常烟叶和病害烟叶的光谱峰位、峰形及吸收强度比有一定差异。为了提高光谱灵敏度,对光谱进行二阶导数相关性分析,五个样品的二阶导数光谱在1750～1500 cm-1和1200～950 cm-1范围内的相关系数差异明显,表明五种烟叶样品所含化学成分或各成分相对含量各不相同,即病害影响烟叶的化学成分。正常烟叶的吸收强度比A1025/     

Nd3+∶Y0.5Gd0.5VO4晶体光谱特性

测量了 0 8at. %Nd3 + ∶Y0 .5Gd0 .5VO4的吸收光谱和荧光发射谱 ,光谱显示该晶体在 80 8 5nm有很强的偏振光吸收峰 ,且π偏振光 (E∥C)吸收远强于σ偏振光 (E ⊥C) 吸收 ,半高宽度分别为 4 5nm和 12nm ,吸收截面分别为 19 6 9× 10 -2 0 cm2 和 6 4 1× 10 -2 0 cm2 ;其荧光发射 (4F3 /2 → 4I11/2 跃迁 )峰值波长在 10 6 4nm ,半高宽度为 3 7nm ;4F3 /2 → 4I11/2 跃迁的荧光寿命为 110 μs;光谱特性表明Nd3 + ∶Y0 .5Gd0 .5VO4晶体是潜在的高效率激光晶体材料     

近红外氧气A带大气透过率的计算

氧气A带具有单一的吸收气体成分和独特的谱线结构,大气中分布相对均匀,在大气辐射研究中具有广阔的应用前景.大气透过率是大气辐射传输计算的核心,为了快速计算大气透过率,提出带平均透过率的数学模型.将近红外氧气A吸收带作为研究对象,以普朗克黑体辐射为基础,分析了氧气A带在762 nm附近波段的光谱吸收理论,介绍了带平均透过率数学模型的原理及方法.为了验证模型的可行性和精确度,结合实验数据,与HITRAN2004数据库逐线积分法计算的透过率进行对比,精度达到2.2％,降低了计算时间.     

T-lymphocyte subpopulations in the blood of patients with chronic B-cell lympholeukemia studied using monoclonal antibodies

The contents of T-lymphocytes and their basic subpopulations (T-helpers and T-suppressors) in peripheral blood of 40 patients with B-cellular chronic lymphatic leukemia was studied (CLL) using monoclonal antibodies. It is shown that an imbalance of T-helpers and T-suppressors is observed in many patients (a ratio of helpers/suppressors less than 1.29 in 24 patients) at the expense of a decrease in the relative content of T-helpers in patients at stage I-III of CLL and an increase in the contents of T-suppressors in patients at stage IV. A correlation is revealed between the ratio of T-helpers and T-suppressors, on the one hand, and the stage of the disease, on the other hand.     

乳腺疾病患者血清的紫外吸收谱分析

测量了不同乳腺疾病患者血清的紫外吸收谱。人血清的紫外吸收谱约在230nm附近有一极强的吸收峰,在279nm有一较强的吸收峰,该吸收峰为蛋白质芳香族氨基酸的特征,在253nm有吸收谷。分析表明,不同乳腺疾病患者血清的紫外吸收谱有差异。血清紫外吸收谱的279nm吸收峰位及1279／1253的差异,反映了样品中芳香族氨基酸的成分及含量的差异;有无414nm吸收峰的差异主要反映了样品是否有溶血发生。这些光谱差异对于乳腺疾病光谱诊断的研究具有参考价值,为应用光谱技术进行血清检测,诊断疾病寻求简便的方法和途径。     

由激光靶冲量耦合实验结果判定激光支持爆轰波点燃阈值

根据激光吸收区等离子体组分与激光功率密度的关系判定激光支持爆轰波(LSDW)的点燃阈值。在激光靶冲量耦合实验的基础上,用悬摆动力学方程计算了激光支持爆轰波对铝靶冲量和冲量耦合系数;继而由靶冲量与激光吸收区膨胀介质(等离子体和气体)比热比的Jouguet条件,以及由二维流体动力学数值模拟获得的激光靶冲量随时间的变化过程,得到了激光吸收区介质的比热比随激光功率密度的变化情况,由此可得激光吸收区介质比热比随激光功率密度的增大而减少的结论;根据等离子体和气体比热比的差异定量分析了不同激光功率密度条件下激光吸收区气体和等离子体的构成。由等离子体含量随激光功率密度的变化关系得到了激光支持爆轰波的点燃阈值在(1.62±0.01)×108~(2.10±0.07)×108W/cm2间的结果。     

The Dipolar Resonance of the Cylindrical Low-Pressure Arc Discharge

When an em wave of fixed frequency is incident on the cylindrical positive column of a low-pressure arc discharge, nearly complete absorption occurs at a definite value of discharge current I/sub 0/ as the discharge current is varied. I/sub 0/ yields a plasma electron density which corresponds to the well-known cylindrical, or dipolar, plasma resonance frequency f/sub 0/. The ratio f/sub p/ / f/sub 0/ where f/sub p/ is the ordinary (plane) plasma frequency, has been determined by others using a quasi-static approach. In this paper a dynamic approach is used, and comparison is made with the quasi-static approach. Agreement is within 3 per cent for values of /spl beta//sub 0/a less than 0.25. For beta//sub 0/a equal to 0.60, the discrepancy in the quasi-static method is 15 per cent. Theoretical calculations as well as experimental evidence indicate that the electron sheath, which exists on the outside surface of the positive column, plays a significant role in the location of the dipolar plasma resonance. Application of the results of this paper improve the agreement between theory and experiment for the Plasma Microwave Coupler described by Steier and Kaufman.     

调制转移光谱的最佳吸收程

调制转移光外差光谱信号的信噪比(SNR)和中心斜率与吸收程等有关.采用吸收程微元叠加法———把吸收程分成n段,计算出每一段产生的调制转移光谱信号元,再对n求和得到总的调制转移光谱信号.利用该方法,理论上研究了调制转移光谱信号相对强度及中心斜率随吸收程的变化,得到最佳吸收程.实验上比较了碘池温度为-15℃时一倍程(40 cm),二倍程(80 cm),三倍程(120 cm)和四倍程(160 cm)的光谱信号信噪比和谱线中心斜率,得到三倍程时信号信噪比和谱线中心斜率为最大,估算得到相应的激光稳频精度为9×10-14(1 s积分时间).通过吸收程优化过程获得的调制转移光谱信号用于激光频率稳定控制,有望获得更高的稳频精度.     

Compact current-mode loop filter for PLL applications

A novel capacitance scaling technique is proposed to reduce on-chip capacitor area using a dual-path self-biased current-mode filter. The capacitor multiplier is obtained by the relative ratio of charge-pump currents I/sub cp2//(I/sub cp2/-I/sub cp1/), rather than the scaling ratio I/sub cp2//I/sub cp1/. Compared with the original current-mode filter, the demonstrated loop filter of 250 pF capacitance is achieved with only 25 pF (90% die area saving), and the resistor area is reduced by 50% owing to reuse of the degenerated resistor R/sub G/.     

Intersubband absorption saturation in InGaAs-AlAs-AlAsSb coupled quantum wells

This paper gives saturation (switching) energy (I/sub S/) estimates in an all-optic switch material based on absorption saturation in InGaAs-AlAs-AlAsSb coupled-double quantum wells (cDQWs). A model based on density matrix theory for a 4-level system is used to simulate the pulsed excitation conditions of the experiment in the communication wavelength region. The theoretical estimates are compared with experimentally determined values. A comparison of the I/sub S/ in two different cDQWs (one with an indium composition in the well of about 53% and without an AlAs stopping layer at the well-barrier interface and another with 72% indium and an AlAs stopping layer) clearly shows that the samples with high indium content are of a better quality compared to those with lattice-matched indium composition (53%). An order-of-magnitude reduction in the I/sub S/ in an all-optic switch based on cDQWs with high indium content is reported.     

Optical properties of AlGaAs/GaAs nipi superlattices and theirapplication in asymmetric cavity spatial light modulators

Homo-nipi and hetero-nipi superlattices incorporated into asymmetric Fabry-Perot cavity structures are compared and evaluated for possible use as bit plane optical memory elements in terms of the magnitude of their optical nonlinearities, on-off contrast ratio, insertion loss, carrier lifetimes, and power required to change the state of the structure. Changes in superlattice absorption coefficient as high as 1500 cm^-1 and 1300 cm^-1 have been achieved in type I and type II AlGaAs/GaAs hetero-nipi structures, respectively. When normalized to the GaAs quantum well layer thicknesses, the change in absorption coefficient in the type I superlattice was as high as 12000 cm^-1. In asymmetric cavity modulator structures, on-off reflection contrast ratios as high as 60:1, carrier lifetimes as long as 4 ms, and on-state reflectivities as high as 0.62 have been observed. A 54:1 contrast ratio and an insertion loss of 8.5 dB were achieved simultaneously in a planar Fabry-Perot cavity structure excited with a pump beam power of 3.8 mW. The effective carrier lifetime in this case was 25 μs     

Vibratonal spectroscopy of <Emphasis Type="Italic">a</Emphasis>-C:H(Co)

The interaction between cobalt and a carbon host was investigated for films of amorphous hydrogenated carbon modified by cobalt. Films of amorphous hydrogenated carbon with various concentrations of cobalt, a-C:H(Co), were grown by the DC magnetron cosputtering of graphite and cobalt targets in an argon-hydrogen plasma. Rutherford backscattering of protons and the method of nuclear reactions were used to determine the relative atomic content of cobalt and carbon in the films. Infrared absorption was investigated in the region of stretching vibrations of the C-C-bond and bending vibrations of the C-H-bond; Raman scattering was also measured. A giant intensification of absorption by the vibrational C-H modes and the appearance of additional C-C modes induced by cobalt were observed. The intensity of the fundamental vibrational modes were analyzed as functions of cobalt content and annealing temperature. The principal mechanisms of interaction between cobalt and the amorphous carbon host is revealed. Thermal vacuum annealing at ～350°C was shown to suppress the cobalt-carbon interaction, which might favor the formation of cobalt nanoclusters in the amorphous carbon host at these or higher temperatures.     

非晶硅太阳电池本征层特性研究

本文研究了不同沉积条件下的未掺杂a-Si:H特性,测量了材料的光致变化、红外吸收谱、光暗电导率、次带吸收谱等。研究表明,电池的稳定性除与弱健、微空洞等缺陷有关外,还与未掺杂a-Si:H中的高硅氢键的含量直接相关。