LED全光谱无级变色灯[套件供应]

使用超高亮度红、绿、蓝色发光二极管LED作光源,配合调光电路,制成全光谱无级变色灯。专利申请号02238279.8。它能够连续柔和地发出红、橙、黄、绿、青、蓝、紫、红……的渐变彩色及全部过渡色。这种变化是无级的,没有突变。实质上它连续发出可见光谱(波长     

基于三(8-羟基喹啉)铝的紫外增强薄膜研究

为了提高硅基成像器件的紫外响应,本文通过对Alq3发光机理与光致发光特性的研究,用真空蒸镀的方法制备出了基于Alq3的有机金属薄膜.通过测量Alq3薄膜的透过率、光致发光光谱和激发光谱,发现Alq3薄膜在可见波段有很好的透过性,用紫外光激发会产生较强的绿光(中心波长位于510 nm),且激发光谱宽(250～425 nm).结论表明Alq3薄膜的发射光谱能够与传统硅基成像器件的响应光谱匹配,是一种符合实际要求的紫外增强薄膜.     

酸、碱性条件下茜素红紫外-可见光谱的量子化学研究

茜素红(ARS)是葸醌类化合物中茜草素型的一种,被广泛应用于电化学、光谱学等领域的研究。在酸性溶液中,茜素红主要在260 nm和422 nm处出现明显的吸收峰,而在碱性溶液中吸收峰移动到272 nm和556 nm。为了分析不同溶液环境对茜素红吸收峰波长的影响,本研究在杂化密度泛函方法B3LYP/6-311+(d)水平上优化了ARS分子在酸、碱性情况时的稳定基态构型,并采用含时密度泛函(time-dependent density functional theory,TD-DFT)方法模拟了ARS分子的电子吸收光谱。计算结果与实验得到的紫外可见吸收光谱相吻合,说明密度泛函理论用来研究茜素红的紫外可见光谱是有效可靠的。通过计算还确定了每个吸收峰对应的各个电子跃迁的贡献率以及Mulliken电荷分布。该理论与实验的结合研究为茜草素型化合物的进一步应用、分子设计、药物构效关系和化学反应规律的研究提供了重要的参考依据。     

典型煤系岩石的可见-近红外光谱特征研究

为研究基于可见-近红外光谱技术的煤岩识别方法,从山西、山东4个煤矿收集了页岩、砂岩、灰岩三大类11种典型煤系岩石,测定了其可见-近红外波段(400～2 450nm)的反射光谱,分析了其矿物、元素组成对反射光谱特征的影响,获得了碳质物质含量对煤系页岩反射光谱曲线特征参数的影响规律。研究结果表明:①绝大多数煤系岩石的反射光谱曲线在可见光波段(400～780nm)和短波近红外波段(780～1 100nm)呈现出随波长增加的多重吸收谷。在长波近红外波段(1 100～2 450nm),明显的吸收谷主要集中在1 400,1 900,2 200,2 350nm波长,页岩、灰岩吸收谷的波长相对固定,而不同砂岩吸收谷的波长呈现出多种变化。②除碳质物质含量较高的碳质页岩外,同一煤矿各类煤系岩石与煤的可见-近红外波段反射光谱吸收特征差异明显。③当煤系页岩中碳质物质含量增大时,可见-近红外波段反射光谱曲线的光谱斜率和各明显吸收谷深度均呈先快速减小后趋于平缓的特点。     

无级变色霓虹灯箱

本文介绍利用本刊上一期介绍过的线性固态继电器XSSR制成的变色灯箱。它能够连续柔和地发出红、橙、黄、绿、青、蓝、紫、红……的渐变彩色及全部过渡色。这种变化是无级的、没有突变。实质上它连续发出可见光谱(波长380—780毫微米)中所有波长的色彩。原理见图1。红、绿、蓝三基色霓虹灯按时序产生有间断三角形的亮度变化,所以是每两种色彩轮流相加混色。从t_0到t_3,得到一个周期的彩色。     

基于平面反射式光栅的微型紫外-可见光谱仪设计

光谱仪具有快速、无损、多元数据分析等显著特点,已成为环境监测、食品安全检测、生物医学、航空航天和国家安全等众多涉及国民经济和安全领域的必备检测装备。但传统的光谱仪体积大、功耗高、成本高,已严重制约现代光谱分析技术的快速发展。微型化成为重要发展方向。针对上述诸多领域对微小型光谱仪的广泛需求,提出一种基于平面反射式衍射光栅的宽光谱、高分辨率微型紫外-可见光谱仪光学系统设计方法。考虑微型光谱仪宽光谱范围与高分辨率的矛盾,提出基于光线追踪的设计并结合系统像差消除方法。通过ZEMAX软件完成光学系统的优化设计,实现了微型紫外-可见光谱仪的宽光谱、高分辨率设计。设计的仪器光谱范围为200～800 nm,在50μm入射狭缝下整个波段的光谱分辨率优于0. 5 nm。该方法可广泛应用于基于平面反射式衍射光栅的宽光谱、高分辨率微型光谱仪光学系统设计。     

遥感器角度响应订正函数的建立

为满足FY-3紫外臭氧垂直探测仪高精度太阳紫外光谱辐照度观测,开展了整机角度响应特性的研究,建立了一套200nm~400nm角度响应定标装置,并基于四阶泰勒级数构建了任意入射角度下光谱辐照度响应度订正函数,在轨数据分析表明相对偏差优于0.5%。     

遥感器角度响应订正函数的建立

为满足FY-3紫外臭氧垂直探测仪高精度太阳紫外光谱辐照度观测,开展了整机角度响应特性的研究,建立了一套200nm~400nm角度响应定标装置,并基于四阶泰勒级数构建了任意入射角度下光谱辐照度响应度订正函数,在轨数据分析表明相对偏差优于0.5%。     

BN_xP_(1-x)光电薄膜的性能及在紫外探测中的应用

通过化学气相沉积法在单晶GaAs衬底上成功生长了BNxP1-x薄膜材料。利用扫描电镜观察到该薄膜表面十分光滑,其生长层与衬底之间具有良好的粘合性,不容易脱落。利用紫外-可见光分光光度计(UV)研究了薄膜的紫外吸收特性。并测量出在254nm和365nm波段其量子效率分别为33%和40%,当波长大于400nm时,其量子效率陡然下降。经研究证明:BNxP1-x作为一种宽带隙半导体材料在日盲型紫外探测领域中具有极大的潜能。     

高斯多峰拟合运用于十二烷基苯磺酸钠聚集状态的研究

分光光度法研究十二烷基苯磺酸钠(sodium dodecyl benzene sulfonate,SDBS)在水中的聚集行为,具体作法是测量一系列不同浓度的SDBS——碱性品红水溶液体系可见吸收光谱,其光谱特征是碱性品红(Fuchsine)单体吸收峰540-570nm和二聚体吸收峰490-530 nm叠合在一起,用Origin软件频谱分析软件包中的高斯多峰拟合法,实现了体系紫外可见光谱吸收叠合峰的分峰、峰面积(积分吸光度)、频移及半高宽计算;单体和二聚体峰面积比(相对积分吸光度A2/A1)、频移(△λ)及半高宽(w1,w2)对SDBS浓度敏感,转折点十分明显,且该转折点对应的浓度为SDBS的临界胶束浓度(critical micelle concentration, CMC)。其中体系紫外可见光谱的半高宽对表面活性剂浓度敏感是首次观察到。     

Detecting photosynthetic algal pigments in natural populations using a high-spectral-resolution spectroradiometer

Reflectance data from a high spectral resolution spectroradiometer were obtained onboard a ship in Plymouth coastal waters. These data were analysed to detect algal photosynthetic accessory pigments for comparison with absorption spectra as measured in the laboratory by a spectrophotometer. The overall spectral characteristics of Plymouth waters allowed identification as to population composition. Derivative analysis of the spectra was used to resolve characteristic peaks of specific pigments. It was determined that chlorophyll pigments, a specific carotenoid and sea water absorption bands were detectable in the reflectance data. Absorption bands of photosynthetic and accessory pigments were assessed through chromatographic pigment analysis.     

The identification of phytoplankton pigments from absorption spectra

The absorption spectra of photosynthetic algae are characterized by a continuous envelope, which is a result of the overlapping spectra of the indivual pigments. This feature makes it difficult to estimate the contribution of each pigment to the total absorption spectra. Derivative analysis is an objective tool for isolating absorption peaks in phytoplankton. Theoretically, electrons and ions of interacting molecules can be regarded as simple harmonic oscillators in an electromagnetic field, which result in a Lorentzian shape. However, when measured by an optical spectrophotometer the signal is transformed into a Gaussian curve. Thus, a combination of both types of curve provides a realistic approach to the decomposition of absorption spectra. In this study derivative analysis is performed on absorption spectra in order to prove that the method can be successfully used to identify the individual absorption spectra of component pigments. The spectra used are modelled phytoplankton, spectrophotometric measurements of algal cultures and samples from natural waters. A combination of Gaussian-Lorentzian shaped curves, centred on the identified peaks, were compared with the original spectra and showed good agreement.     

岩石实验室反射光谱的相似系数聚类分析

以n维向量空间中的向量夹角为分类依据,对内蒙乌拉尔山地区53个岩石实验室反射光谱进行相似系数聚类分析,揭示出0.4～2.5μm岩石谱形的总体相似性差异。结果表明,岩石的电磁波属性不同于岩石学的分类属性,提出按谱形的相似性对岩石进行归类的方法及其意义。同时分析了成像光谱技术中光谱角度填图方法的优劣及改善措施,为成像光谱图像处理方法提供了十分有意义的光谱依据。     

植物花色模式仿真

利用反应-扩散系统与颜色的频谱表达体系,将色素分布仿真与色素颜色表达相结合,并统一在同一个系统框架内,以对植物花色模式进行仿真.首先使用经植物脉络信息修正后的反应一扩散系统对色素分布进行仿真,然后用与传统的基于手绘或照片等不同的基于色素吸收光谱的方法来获得数据.该系统可通过调整参数实现对现实世界中大量不同植物花色模式的仿真,而且可嵌入其他系统,以改进它们的渲染效果.     

Computational Creation of Hollow Mask Type Illusionary Solids with Shading Effect

"Hollow mask illusion" is an optical illusion and appears due to an error in the process of reconstructing the three-dimensional objects from our two-dimensional retinal image. In this paper, we present a computational method to create "Hollow mask" type new illusionary solid by calculating the hollow structure and its shading. The straight line Voronoi diagram for a given shape obtains the three-dimensional vertices of the hollow structure and the shading effect on each surface is calculated under the assumption that each surface has diffusely reflecting surface(Lambertian reflectance). We also show two examples of our new illusionary solid works.     

Detection and correction of adjacency effects in hyperspectral airborne data of coastal and inland waters: the use of the near infrared similarity spectrum

A method for the detection and correction of water pixels affected by adjacency effects is presented. The approach is based on the comparison of spectra with the near infrared (NIR) similarity spectrum. Pixels affected by adjacency effects have a water-leaving reflectance spectrum with a different shape to the reference spectrum. This deviation from the similarity spectrum is used as a measure for the adjacency effect. Secondly, the correspondence with the NIR similarity spectrum is used to quantify and to correct for the contribution of the background radiance during atmospheric correction. The advantage of the approach is that it requires no a priori assumptions on the sediment load or related reflectance values in the NIR and can therefore be applied to turbid waters. The approach is tested on hyperspectral airborne data (Compact Airborne Spectrographic Imager (CASI), Airborne Hyperspectral Scanner (AHS)) acquired above coastal and inland waters at different flight altitudes and under varying atmospheric conditions. As the NIR similarity spectrum forms the basis of the approach, the method will fail for water bodies for which this similarity spectrum is no longer valid.     

Using vegetation reflectance variability for species level classification of hyperspectral data

A study was conducted to investigate whether reflectance data from vegetation in a tropical forest canopy could be used for species level discrimination. Reflectance spectra of 11 species were analysed at the scale of the leaf, branch, tree and species. To enhance separation of species-of-interest spectra from the other spectra in the data, the variation in reflectance values for the species-of-interest were used to create a characteristic spectral shape. With a simple algorithm, the resultant shape-space was used as a data filter that correctly discriminated against 94% of the non-species-of-interest trees.     

Field spectroscopy of estuarine intertidal habitats

The recent introduction of portable, low‐cost hyperspectral radiometers for measuring the reflectance of marine intertidal habitats has considerable promise, first as a source of reference spectra for airborne and satellite remote sensing, and second as a survey technique in its own right. This paper reports on the results of an intercalibration exercise in which two designs of commercially available instruments were used to measure reflectance spectra across a diverse, intertidal site. The substrates sampled included seagrasses, macroalgae, and sediments which varied in wetness and grain size. Spectra were compared statistically using several measures of similarity, and the results showed a high degree of correlation between the measured reflectance spectra. There were no significant differences between instruments from different manufacturers in the shape of reflectance spectra, but the signal‐to‐noise ratio varied considerably between individual instruments. Spectra measured by operators with lesser experience in field spectrometry tended to be more variable than those of more experienced operators, indicating that training and adherence to set protocols are important when implementing this method in the field situation. Spatial plots derived from field spectra showed essentially the same trends in surface features as plots created using traditional sampling and remote sensing methods. Furthermore, the use of field spectrometry as a stand‐alone, low‐cost method for rapidly mapping the distribution of major habitat types was demonstrated by the results of a survey of a large intertidal sandbank.     

Mapping microphytobenthos biomass by non-linear inversion of visible-infrared hyperspectral images

This study presents an innovative approach to map microphytobenthos biomass and fractional cover in Bourgneuf Bay (French Atlantic coast) using Digital Airborne Imaging Spectrometer (DAIS) hyperspectral data. Microphytobenthos is a microalgae forming a biofilm on the mudflat. Its spatial distribution is heterogeneous so it varies on a finer scale than that of airborne instrument spatial resolution, leading to a “mixed pixel” problem. Moreover, some microphytobenthic species form, at low tide, a biofilm deposited at the surface of the sediment substrate. The resulting signal is a highly non-linear combination of spectral endmembers due to microscale intimate mixtures. This prevents the use of classical linear unmixing models to retrieve biomass from reflectance spectra. A Modified Gaussian Model (MGM) is therefore used to remove the effects of surface roughness, shadowing and any other unknown processes that contribute to the overall shape (continuum) of the reflectance spectra. Then, relationships between microphytobenthos biomass and spectral shapes are derived from a spectral database compiled from laboratory reflectance spectra of microalgal monospecific cultures with different biomasses. Finally, microphytobenthos biomass and fractional cover are retrieved from the DAIS image by comparing the reflectance spectra of each pixel to a library of synthetic spectra corresponding to combinations of various biomasses and substrate percent cover. This new approach, when compared to more classically used ones such as indices, linear unmixing or spectral distance analysis, is proven to enable a much more reliable determination of biomass despite the large variety of substrates found in Bourgneuf Bay.     

An investigation on photopolymer solidification considering laser irradiation energy in micro-stereolithography

Micro-stereolithography technology has made it possible to fabricate freeform three-dimensional microstructures. This technology is based on conventional stereolithography, in which a UV laser beam irradiates the free surface of a UV-curable liquid photopolymer, causing it to solidify. In micro-stereolithography, a laser beam that is a few m in diameter is used to solidify a very small area of the photopolymer. Photopolymer solidification phenomena in response to variations in the scanning pitch of a focused laser beam were investigated experimentally in this study according to the irradiation energy. The effect of the layer thickness on the solidification width and depth was also examined. The study was conducted using both a relatively low laser power and high scanning speed (low irradiation energy method), and a relatively high laser power and low scanning speed (high irradiation energy method). The experimental results were compared with those obtained using a photopolymer solidification model. Based on these results, a new laser-scanning scheme is proposed according to the three-dimensional microstructure shape desired. Samples were successfully fabricated using both methods.This research was supported by the Center for Nanoscale Mechatronics and Manufacturing (CNMM; http://www.nanomecca.re.kr), which performs some of the 21st Centurys frontier R&D projects, and sponsored by the Korean Ministry of Science and Technology under the contract project code M102KN010001–02K1401–00211.