高压下Na5Eu(WO4)4的光谱和晶场参数

四钨酸铕钠Na5Eu(WO4)4是化学计量的基质发光材料,发光来源于基质中高浓度的Eu3+.本工作用金刚石对顶砧显微高压光谱系统,在0～8GPa范围内研究了Na5Eu(WO4)4的Eu3+室温光谱,确定了各发射谱线在高压下的红移率.根据晶场理论,确定了Eu3+各能级用晶场参数表示的公式,并与高压下谱线位置实验值定出的能级值拟合,计算出晶场参数Bkq(kq=20、40、44、60、64)随压力的变化率ΔBkq/ΔP.     

Con-A诱发的淋巴细胞化学发光

本文以刀豆素 A(ConA)为诱发剂,研究了绵羊肺淋巴液中的淋巴细胞鲁米诺依赖的化学发光现象.结果表明,ConA诱发的淋巴细胞化学发光测定具有迅速、简便和敏感等优点,可作为淋巴细胞活化的检测方法.淋巴细胞悬液(106～107个细胞/ml)1ml、ConA溶液(2mg/ml)0.1ml、鲁米诺溶液(10-3M)50μl为最佳测定体系.多形核白细胞(PMN)混杂可明显增强发光体系的发光强度.因此,测定外周血中的淋巴细胞化学发光,细胞的纯化是一个不可忽视的问题.消炎痛可抑制其发光,说明发光可能与花生四烯酸代谢有关.     

用电致发光屏制作文字、数字显示器

随着现代信息化社会的发展,连接人与信息的显示器件日益引人注目.显示器件包括阴极射线管(CRT)、等离子体显示屏(PDP)、液晶显示屏(LCD)、电致发光屏(EL屏)等.在这些显示器件中,CRT有以下几个缺点:(1)管身长;(2)真空器件易损坏;(3)难于克服扫描畸变;(4)电压高.然而CRT能用电子透镜系统把电子束聚焦偏转,使所需象元发光,并且方便,所以至今仍作为显示的主流而广泛使用着.     

α-Al2O3单晶的热释光和光释光特性

研究了纯α-Al2O3单晶的热释光发光曲线和三维发光谱,以及光释光衰变曲线,对它们的发光机理和剂量学特性进行了分析和讨论.实验观察到α-Al2O3单晶β射线照射后立即测量的热释光发光曲线,有峰温为76℃和207℃两个发光峰.经γ射线照射数小时后测量的三维发光谱,只有峰温207℃波长为416 nm发光峰,它与α-Al2O3:C晶体的发光波长基本相同,是受热激发到导带的电子与F+心复合所生成的F心激发态3P跃迁至基态1S发的光.用热释光动力学方程拟合不同照射剂量的发光曲线,207 ℃发光峰的峰温基本不随剂量而变化,形状因子μg的平均值为0.415±0.001,该发光峰的剂量响应为线性-亚线性,表明它基本符合一级动力学模型所预言的发光峰.实验还测定了纯α-Al2O3单晶辐照不同剂量后,470 nm波长激发的光释光衰变曲线.用两个指数衰变函数拟合光衰变曲线得到的衰变时间常数τ1(平均值为2.63±0.07s)基本不随剂量而变化,而τ2则在0.12至12 Gy范围内有明显下降趋势,大于12 Gy时无明显变化,约75s.时间常数τ1对应的光释光强度和吸收剂量的关系为线性-亚线性.     

中国物理学会发光分会第10届会员代表大会会议纪要

中国物理学会发光分会第10届会员代表大会于2007年8月22日在长春召开。参加本次代表大会的会员代表共140余人。会议由发光分会上届委员会副主任王永生教授主持。会上,首先由发光分会上届委员会主任范希武研究员作第9届委员会(2004年8月～2007年8月)的3年工作总结报告。报告共分3部分:(1)发光分会发展的历史回顾;(2)本届委员会任期的工作汇报;(3)对今后发光分会工作的建议。然后由秘书长申德振研究员就中国物理学会发光分会章程的修改以及发光分会第10届委员会30名委员候选人的酝酿、产生和确定过程作了介绍。自2004年8月始,发光分会委员会在…     

CaSO4∶Eu磷光体的热释光特性研究

用热释光三维发光谱仪和蓝色滤光片的热释光仪测定了CaSO4:Eu2+的辐照后的发光曲线,得到峰温为107和144℃波长390nm的发光峰.辐照50d后,107℃发光峰已衰退,发光曲线呈现144℃单个发光峰.经一级力学方程式拟合得到的激活能E=(1.02±0.03)eV与初始升温法(1.07±0.01)eV和峰形法(1.02±0.01)eV的非常符合.用通用级动力学模型拟合发光曲线,得到陷阱能级E=(1.04±0.01)eV,频率因子s=(2.07±0.8)×1012s-1和动力学级数b=1.05±0.02 关键词： CaSO4∶Eu 剂量响应 动力学参量 热释光     

吖啶酯化学发光测量参数和睾酮抗体工作浓度的最佳化

10-甲基吖啶-9-羧酸[4-(N-睾酮-3-羧甲氧基肟)-氯乙基]苯酯(To-3-AEPMAC)发光测量的时间参数在低浓度区域测量十分重要.本文报道在0.00～0.21s间有一占发光总面积4.10±2.21%(x±s)的溶剂峰;峰发光的起始和终点在0.32～3.915间,峰时间参数位于0.43～2.22s间,反应速率分析也证实时间参数的实验结果.选择0.30s延迟时间和10s积分时间的化学发光积分参数测量既可排除溶剂发光的干扰,又可较精密地采集到T0-3AEPMAC的全部发光信号.而单位时间的发光峰高测量因随剂量增加峰时间参数延长不能满足建立超微量化学发光免疫化学分析测量的要求.本文根据化学发光免疫化学高灵敏和高精密的分析要求,通过抗体稀释曲线极值的优选、最大反应变化的标定和最小反应标准误点分析使睾酮抗体的工作浓度最佳化,即稀释度为1:18000.     

美国电化学学会一九八○年春季会议

会议将于1980年5月11—16日在圣路易市召开。关于发光方面的内容分三部分: 1.发光粉的老化:会议建议的讨论题目有:(1)发光粉老化方面最近的观点、理论;(2)光化学现象;(3)色心的形成和有关的光学效应;(4)CRT器件中的电子灼烧问题;(5)汞灯中发光粉与汞的相互作用问题;(6)与发光粉老化有关的表面研究,例如,扫描电镜、化学分析的电子光谱,俄歇光谱研究等;(7)在新的应用条件下的发光粉老化问题,例如低功率灯、高电流负载、无电极灯和CRT中的高束流等。     

MA0.6Cs0.4PbBr3钙钛矿发光二极管瞬态电致发光研究

为研究钙钛矿材料的发光特性和机理,制备了稳定的MA_(0.6)Cs_(0.4)Pb Br_3钙钛矿发光二极管,通过瞬态电致发光测试,分析了器件在脉冲电压下的电流和发光曲线。MA_(0.6)Cs_(0.4)Pb Br_3发光二极管在恒定的电流密度10 m A·cm~(-2)下,亮度从最大值衰减至一半持续时间超过30 min,保证了瞬态测试的准确性。在0.1～20 ms脉宽测试中,器件发光效率随时间增加,断电后有反向电流;在5.5～8.0 V的脉冲幅值测试中,低电压的亮度最先达到饱和;在0～2.0 V基准电压测试中,高基准电压时亮度值更低。分析瞬态测试结果,发现离子迁移(MA~+,Br~-)导致钙钛矿层的界面附近发生能带弯曲,使得载流子注入减弱,同时抑制了激子的离化,提高了激子复合几率。     

快重离子辐照对非晶态SiO2薄膜光致发光谱的影响

用湿氧化法在单晶硅表面生长了非晶态SiO2薄膜,再用高能Pb和Xe离子对薄膜进行辐照,最后用荧光光谱分析了辐照参数(剂量、电子能损值)与发光特性改变的相关性.研究发现,快重离子辐照能显著影响薄膜的发光特性,进一步分析显示,辐照导致了SiO2薄膜内O-Si-O缺陷、缺氧缺陷和非桥式氧空位缺陷的产生,且缺氧缺陷和非桥式氧空...     

Mechanism of low-frequency discrete acoustic emission during intermittent creep of aluminum alloy

A correlation between the dynamics of deformation bands and the discrete acoustic emission during the intermittent creep of the AlMg6 alloy using a high-speed video recording with a time resolution to 50 μs has been studied. A trigger of a macroscopic deformation step in the creep curve is the nucleation and the broadening of the primary deformation band that generates a characteristic acoustic emission signal with duration of several milliseconds. The results confirm the mechanism of generating an acoustic emission signal related to the cooperative dislocations outcrop on the specimen external surface.     

Optimization of high pressure processing parameters of Indian white prawn (Fenneropenaeus indicus)

The effect of pressure (150, 250 and 350?MPa), ramp rate (200, 400 and 600?MPa/min) and holding time (3, 6 and 9?min) on the quality indices (dependent variable) of Indian white prawn (Fenneropenaeus indicus) was optimized using response surface methodology. Box–Behnken response surface design was used with 15 runs. Second-order response surface model was fitted to the experimental data and the model adequacy was measured by R² value. The linear and quadratic effect of pressure, ramp rate and holding time was significant for tri-methylamine, total volatile base nitrogen and total plate count. Based on the ridge analysis and response surface plots, the optimum combination obtained was 250?MPa pressure, 400?MPa/min ramp rate and 6?min holding time for high pressure (HP) processing of Indian white prawn. Validation of the experiment indicated that the developed model was appropriate to predict quality indices in Indian white prawn processed by HP processing.     

人体腿部四层结构的红外热成像有限元分析

为研究人体红外热成像和体内肿瘤热源的关联,本文构建了包括骨层、肌肉层、脂肪层、皮肤层的人体腿部有限元模型。根据体内温度沿径向分布的特点,给出了各区域内动脉血液灌注热生成率随径向坐标变化的情况,解决了有限元建模中动脉血灌注热生成率随温度变化的非线性问题。进而用有限元方法数值计算了不同尺寸和不同深度的体内肿瘤所带来的温度变化。结果表明：在所研究的肿瘤尺寸范围内,肿瘤尺寸越小,体内温度提升越高,体表的峰值温度越高,体表温度分布半峰宽越窄,温度变化越陡峭。对于特定尺寸的肿瘤,肿瘤越深,体内峰值温度越高,体表的峰值温度越低,体表温度分布半峰宽越宽,温度变化越平缓。     

Effects of the Sagittarius dwarf tidal stream on dark matter detectors

The Sagittarius dwarf tidal stream may be showering dark matter onto the solar neighborhood, which can change the results and interpretation of direct detection searches for weakly interacting massive particles (WIMPs). Stars in the stream may already have been detected in the solar neighborhood, and the dark matter in the stream is (0.3-25)% of the local density. Experiments should see an annually modulated steplike feature in the energy recoil spectrum that would be a smoking gun for WIMP detection. The total count rate in detectors is not a cosine curve in time and peaks at a different time of year than the standard case.     

Surface analysis of thermally annealed porous silicon

Quasi-monocrystalline porous silicon (QMPS) has high potential for photovoltaic application for its enhanced optical absorption compared to bulk silicon in the visible range of solar spectrum. In this study, QMPS was formed from low porosity (∼20-30%) porous silicon (PS) produced by electrochemical anodization, and thermal annealing in the temperature range 1050-1100 °C under pure hydrogen ambient for a duration of 30 min. We analyzed the material surface by grazing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and dynamic secondary ion mass spectroscopy (SIMS) study. The crystallinity was confirmed by GIXRD while FESEM studies revealed that the surface layer is pore free with voids embedded inside the body. AFM studies indicated relatively smooth and uniform surface and the dynamic SIMS study showed the depth profiles of impurities present in the material.     

时间相关单光子计数中几个基础问题

本文详细讨论了时间相关单光子计数技术中几个基本物理过程和数理统计原理,实际测量中要注意的几个问题和性能的基本估价。     

Constructive and destructive interference in acoustic emission during fatigue crack propagation

Fatigue crack propagation monitoring with acoustic emission reveals the presence of maxima and minima in the curve of the count rate as a function of the stress intensity factor. This is explained in terms of constructive and destructive interference due to specimen geometry. A theoretical model is developed and experimental proof of the validity of the model is presented.     

Surface effects on photoluminescence of single ZnO nanowires

The influence of surface effects on the temperature dependent photoluminescence (PL) spectra from individual ZnO nanowires has been studied. It is found that the surface effects of the nanowire are very important in both ultraviolet (UV) and visible emission. We propose a new luminescence mechanism based on the recombination related to oxygen vacancies to explain the temperature dependent visible emission, which is significantly influenced by the carrier depletion and band bending caused by surface effects. In addition, the observed attenuation of UV emission with increasing temperature is ascribed to the decreasing depletion region and the increasing surface states related nonradiative recombination.     

磷青铜表面合金镀层的辉光放电发射光谱逐层分析

应用辉光放电发射光谱分析技术，从纯金属求得难以测定的试样表层合金的溅射率，对磷青铜薄带的镀层（Ａｇ－Ｃｕ）合金进行表面逐层分析，得到镀层中银和铜含量随深度的变化曲线，同时测得了镀层的厚度。     

AG-013736, a novel inhibitor of VEGF receptor tyrosine kinases, inhibits breast cancer growth and decreases vascular permeability as detected by dynamic contrast-enhanced magnetic resonance imaging

Dynamic contrast-enhanced MRI (DCE-MRI) was used to noninvasively evaluate the effects of AG-03736, a novel inhibitor of vascular endothelial growth factor (VEGF) receptor tyrosine kinases, on tumor microvasculature in a breast cancer model. First, a dose response study was undertaken to determine the responsiveness of the BT474 human breast cancer xenograft to AG-013736. Then, DCE-MRI was used to study the effects of a 7-day treatment regimen on tumor growth and microvasculature. Two DCE-MRI protocols were evaluated: (1) a high molecular weight (MW) contrast agent (albumin-(GdDTPA)(30)) with pharmacokinetic analysis of the contrast uptake curve and (2) a low MW contrast agent (GdDTPA) with a clinically utilized empirical parametric analysis of the contrast uptake curve, the signal enhancement ratio (SER). AG-013736 significantly inhibited growth of breast tumors in vivo at all doses studied (10-100 mg/kg) and disrupted tumor microvasculature as assessed by DCE-MRI. Tumor endothelial transfer constant (K(ps)) measured with albumin-(GdDTPA)(30) decreased from 0.034+/-0.005 to 0.003+/-0.001 ml min(-1) 100 ml(-1) tissue (P<.0022) posttreatment. No treatment-related change in tumor fractional plasma volume (fPV) was detected. Similarly, in the group of mice studied with GdDTPA DCE-MRI, AG-013736-induced decreases in tumor SER measures were observed. Additionally, our data suggest that 3D MRI-based volume measurements are more sensitive than caliper measurements for detecting small changes in tumor volume. Histological staining revealed decreases in tumor cellularity and microvessel density with treatment. These data demonstrate that both high and low MW DCE-MRI protocols can detect AG-013736-induced changes in tumor microvasculature. Furthermore, the correlative relationship between microvasculature changes and tumor growth inhibition supports DCE-MRI methods as a biomarker of VEGF receptor target inhibition with potential clinical utility.