Assessment of Long Term UV Radiation Measured by the Brewer Spectrophotometer in Hong Kong during 1995-2005

Time series of daily UV radiation measured by the ground-based Brewer spectrophotometer #115 in Hong Kong during 1995-2005 were studied through statistics analysis, with focus on the variability and long term changes in relation to total ozone, clouds and AOD (Aerosol Optical Depth). The 11-year mean UV daily dose is 2644±262 J/m2, with maxima(3311 J/m2) in 2000 and minima (2415 J/m2) in 2002. The data were compared with that from TOMS (Total Ozone Mapping Spectrometer) Version 8 and show general agreement between the two. However, the Brewer UV measurement is about 10% lower compared to TOMS data. Apart from the common-known strong seasonal cycle, 26 month periodical was resolved by use of wavelet analysis, which was believed to be associated with quasi-biennial oscillation (QBO) of general circulation. In cloudy days, the annual mean UV daily dose decrease 3.5% to 44.5% compared to clear days. It was also found that surface UV irradiance has close relation to air pollution. Under clear sky condition, 1% AOD increase will lead to 0.2% UV decrease. While global UV radiation increase due to the worldwide observed ozone depletion, investigations indicate that this trend is not significant in Hong Kong during the last 11 years. The possible causes can be attributed to the compensative effect from two aspects. One is the increase of UV resulting from the reduction of clouds with rate of 0.56/10 yr. The other is the decrease of UV due to the enhancement of total ozone and AOD with a rate of 4.23 DU/10 yr and 0.33/10 yr, respectively.

A Novel Chip-based Spectrophotometer for Online Detection

A chip-based spectrophotometer integrated with optical fiber is successfully demonstrated.Grade concentration of lactate solution flowed through the chip to perform an online detection.The response time (100s)and Limit of Detection (LOD, 50mg/L)of the device were measured.This device shows comparable performance with traditional commercial instrument, while greatly decreases the sample requirement per detection and reduces the size of total system,introducing a novel method for real-time detection.

THE LIGNIN CONTENT IN BLACK LIQUID OF STRAW AS-AQ BY ULTRAVIOLET SPECTROPHOTOMETER

The measurement of lignin content in black liquid of straw AS-AQ by ultraviolet spectrophotometer(UV) is discussed in this paper. Different dilution multiple and contrast solutions have an effect on the measured results of the lignin content by UV. The calculation method for the absorption coefficient and the scanning spectrum property of liquor acidified by SO2 are introduced in this paper.

Determination of Thioglucoside in Cabbage by Using the Ultraviolet-visible Light Spectrophotometer

The ultraviolet-visible light spectrophotometer method was adopted to determine thioglucoside in cabbage with the seeds.Individual plant of cabbage was used as test materials,palladium chloride as complexing agent and sodium cellulose glycolate as dispersing agent.The results showed that palladiumd thioglucoside method could be taken as a quick,easy and precise quantitative analysis method to determine thioglucoside in cabbage.

Transmittance Spectrum of Unbranded Sunglasses Using Spectrophotometer

Background: The sunglass standards are not strictly implemented in many countries except Aus-tralia. The purpose of the study was to evaluate the optical properties of unbranded sunglasses for light transmittance. Methods: Unbranded sunglasses with no information about their specifications were included. They were allocated to two groups based on their prices;the ones > 25 US$ (Group A) and the cheaper ones (Group B). Their transmittance spectrum was measured between 190 nm and 900 nm using a double beam scanning spectrophotometer. The European standard for sunglasses was used to evaluate their compliance regarding ultraviolet radiation (UVR) transmittance and minimum requirement for wearing when driving. Results: Thirty-eight sunglasses (Group A = 20 and Group B = 18) were evaluated. Four sunglasses in each group were non-compliant. Percentage transmittance of visible light was <8% in five sunglasses of Group A and in three of Group B, so these were not appropriate to wear when driving. Totally six sunglasses of Group A and five of Group B were non-compliant and/or inappropriate to wear when driving. Conclusions: Based on our findings about their UVR protection and visible light transmittance %, eye care professionals must warn people against the use of unbranded sunglasses without any information about their specifications.

Spectrophotometer standardization in UV-Vis spectral region

Ultraviolet-visible（UV-Vis）spectrophotometry is commonly used in analytical laboratories for qualitative and quantitative analyses.To make the data obtained reliable,an experimental instrument must be calibrated.National Institute for Standards（NIS）in Egypt builds up aphotometric method to ensure the competence of absorbance and transmittance to the standard international and national requirements.This paper presents an instrument for UV-Vis measurement,discusses the factors affecting measurement reliability and estabishes the uncertainty model including correspoding measurement parameters.

The Effectiveness of a Portable Fluorescence Spectrophotometer for Early Detection of Oral Cancer

Purpose: To investigate whether photodynamic diagnosis (PDD) using a portable fluorescence spectrophotometer (FC-1) can easily and objectively discriminate between normal and tumor cells at the dental chairside, and to further compare it with PDD that requires speculum examination by focusing on protoporphyrin IX (PPIX). Methods: Three cell lines (2 human oral squamous cell carcinoma-derived cell lines, HSC-2 and HSC-3 cells, and oral keratinocytes, HOK cells) were cultured. 5-Aminolevulinic acid hydrochloride (5-ALA) and deferoxamine mesylate (DFO) were mixed in DMEM, and the mixture was set to Control (DMEM only) and PDD (5-ALA+DFO) groups. And then, a fluorescence was measured under room temperature (RT) and 37°C (Incubation) by using FC-1. In this study, the two conditions were combined with the Control and PDD groups to form the Control/RT, Control/Incubate, PDD/RT, and PDD/Incubate groups. Additionally, the amount of singlet oxygen (1O2) generated by irradiation with 405 nm LED was measured using electron spin resonance spectroscopy to detect PPIX in the cell supernatant after 24 hours. Results: In HSC-2 and HSC-3, the fluorescence intensity values increased significantly at 2 hours between the Control/RT and PDD/RT groups. In addition, there was a significant difference between HSC-2 and HSC-3 compared to HOK. In all cell lines, the fluorescence intensity values of the PDD/Incubate group were significantly higher than those of the PDD/Control group. The amount of 1O2 generated by 405 nm LED irradiation was higher in the cell supernatants of all cell lines in the order of Control/RT < Control/Incubate < PDD/RT < PDD/Incubate group, and HSC-3 in the PDD/Incubate group showed a significant increase compared to HOK. Conclusion: It is suggested that PDD using FC-1 can clearly distinguish between normal cells and tumor cells in vitro studies using cell lines at 2 hours under 37°C, and it can detect not only intracellular PPIX, but also extracellular PPIX.

Determination of Palladium II in 5% Pd/BaSO₄by ICP-MS with Microwave Digestion, and UV-VIS Spectrophotometer

Determination palladiums have been reported 5% (w/w) Pd/BaSO4 known as Rosenmund Catalyst. The determination of palladium II known as Rosenmund Catalyst is always an expensive procedure usually involving procedures such as flame atomic absorption spectrophotometry, emission spectrometry, and many spectrophotometric methods. In this study, palladium II in 5% Pd/BaSO4, was synthesized and employed to develop an extractive UV-Visible Spectrophotometric, and an inductively coupled plasma mass spectrometry ICP/MS methods for the determination of palladium II. Specification for Pd is 4.85% to 5.10%;the result was 4.97% for the UV-Visible spectrophotometer and 4.90% for the ICP/MS. Both results meet the requirements.

Hyper Gravity-Induced Transients in <i>Phycomyces</i>as Measured by Single Beam Spectrophotometer on the Sounding Rocket TEXUS 50

In the first paper of two referring to the TEXUS 50 campaign using micro dual wavelength spectrometers (MDWS) we kinetically determined the threshold1 for GIACs (gravity-induced absorption changes) in Phycomyces to be lower than 25 × 10&minus;3 g (http://file.scirp.org/pdf/JMP_2015082810060783.pdf). In this second paper, we attended measurement of GIAC-spectra. Unexpectedly, during the upwards movement, i.e. the hypergravity phase up to top acceleration values reaching 11.6 g at 35.4 s after liftoff we observed transient GIAC-spectra ranging from 380 to 750 nm. In addition, during the whole acceleration phase of 68.2 s, another component near 700 nm develops which remains stable during the whole “free fall trajectory parabola” for 381.3 s. The subsequent reentry of the rocket leads to extraordinary deceleration values up 37.8 g, completely destroying Phycomyces sporangiophores excluding their spectral measurement. During the microgravity phase and by centrifuge operation we were unable to detect any GIAC-spectra (in contrast to kinetic MDWS-measurements, first paper).

The Color of Natural Teeth Investigated by Visual Perception and Spectrophotometer

The advantage of electronic devices is to eliminate the subjectivity. Based on individual capabilities, visual perception has its disadvantages. The aim of this study was to find out the possible shade difference between the upper and lower teeth, visual perception versus spectrophotometry as well as proving that females are better in visual perception of colour matching. 82 subjects (dental students) of this study determined the color of each other’s natural teeth. The color of 1640 teeth (incisors, canines and premolars), was matched by visual perception and by Vita Easyshade spectrophotometer. The matching was focused on the middle third of buccal surfaces of the examined teeth. In this study, it was found that there was a difference of color between the teeth of the upper and lower jaw. The percentage of the accordance between two methods was 28.35% for all examined teeth. The color determination at central incisors showed the highest value of accordance 40.85%. Based on Vitapan 3D Mastershade, the most frequent color was 2M2.

组装式紫外可见分光光度计应用于教学实验的探索

介绍了本科生利用散装元件组装紫外可见分光光度计,并将其应用于邻二氮菲测定铁含量实验的探索过程。学生们完成了从实验仪器组装调试到实验应用的全流程探索,从而对仪器的内部结构和功能有了更清晰的认识,对信号采集及处理有了初步了解,并对分析仪器的理论知识有了更深入的理解,有助于培养学生动手能力和创新思维能力,提高其解决问题的能力。

荧光分析法测定美洲大蠊中多肽含量研究

荧光分析法是一种经济快速的分析方法,具有灵敏度高、选择性好、操作简单等优点。鉴于美洲大蠊多肽(DPSFNSWG-NH_(2))自身具有荧光的特性,通过实验建立一种美洲大蠊多肽(DPSFNSWG-NH_(2))的荧光检测新方法。实验结果表明,在最佳条件下,美洲大蠊多肽(DPSFNSWG-NH_(2))在0.12~31.25μg/mL浓度内与荧光强度之间具有良好的线性关系,线性回归方程为y=10.698x+14.625,R^(2)=0.994 2,检测限为0.09μg/mL,将所建立的新方法用于美洲大蠊药材中其多肽(DPSFNSWG-NH_(2))的测定,回收率为85.50%~89.47%。本研究方法操作简便、快速、准确,具有良好的分析应用前景,可用于美洲大蠊中DPSFNSWG-NH_(2)多肽的含量测定。

生物学实验室三种常用仪器的使用注意事项

在生物学本科生和研究生的培养过程中,仪器设备的很多操作细节往往被忽视,导致仪器设备被损坏、实验失败甚至安全事故。根据学生在设备操作中经常出现的问题和实验室教师的工作经验,该文系统总结了生物学实验室中最常用的三种实验设备的注意事项。以这些注意事项为例,阐述培养学生细节意识的重要性,为提高学生的实验技能提供参考。

基于自适应滤波的暗电流消除设计

暗电流作为光电探测器的固有噪声,是影响双光束分光光度计检测性能的重要因素。为消除此影响,提出自适应滤波双光束分光光度计。首先,设计实时暗电流检测系统,能在每个检测周期内捕获样品信号、参考信号和暗电流信号。其次,针对时域差异引起的暗电流消除问题,引入自适应级联滤波算法(Recursive Least Squares and Normalized Least Mean Squares,RLS-NLMS),算法采用三级级联滤波模型,一级局部均值(Local Mean,LM)降低暗电流与检测信号之间的相关性,二级低阶RLS滤波器用于检测信号滤波,三级高阶NLMS滤波器用于处理RLS输出信号。实验结果显示,自适应滤波双光束分光光度计的透射比相对误差仅为1.46%,较传统方法降低了66%,在暗电流消除方面表现出色,具有实际应用价值。

紫外分光光度计法测定硝化纤维素含氮量

为发展绿色无毒、操作简单且结果准确的NC含氮量测量方法,基于硝化纤维素(NC)在碱液中水解后产生的亚硝酸根(NO_(2)^(-))与硝酸根(NO_(3)^(-))的摩尔比与NC含氮量之间的线性关系,采用紫外分光光度计法分析了NC含氮量。在相同的反应条件下水解5种已知含氮量的NC标品,通过紫外分光光度计测定了水解液中的NO_(2)^(-)和NO_(3)^(-)含量,对测量体系的反应条件进行了优化;通过最小二乘法确定NO_(2)^(-)和NO_(3)^(-)的摩尔比(y)与NC标品含氮量(x)之间的线性关系;最后用3种验证用NC样品对此法进行验证。结果表明,通过紫外分光光度计可同时测定碱解液中NO_(2)^(-)和NO_(3)^(-)的含量,其最佳反应条件为:氨基磺酸浓度为20 g·L^(-1),反应时间为30 min;在最佳反应条件下得到了R2为0.9893的y与x间的线性关系式;验证结果表明,采用紫外分光光度计法得到的含氮量与实际含氮量非常吻合,相对标准偏差RSD(n=4)均小于0.150%。

铜铝复合氧化物的制备及催化甲醛降解反应

利用柠檬酸与氢氧化铜、氢氧化铝的酸碱反应制备柠檬酸铜铝复合盐,经500℃热分解制备出了铜铝均匀分布的铜铝复合氧化物。复合氧化物的结构及元素分布采用X射线衍射仪、X射线光电子能谱仪及透射电子显微镜-能谱联用技术进行了表征。以30%过氧化氢溶液为氧化剂,以铜铝复合氧化物为催化剂催化水中甲醛的降解,在25℃、过氧化氢浓度为80μmol/mL、甲醛浓度为0.998 mg/mL,通过分光光度法测定剩余甲醛含量并计算甲醛降解率为95.3%。通过加入自由基捕捉剂叔丁醇验证了该反应机理为自由基反应。实验考察了甲醛浓度、催化剂浓度、过氧化氢浓度及酸碱度对甲醛降解效果的影响。实验发现当甲醛浓度小于0.998 mg/mL,催化剂浓度为16 g/L,过氧化氢浓度为80μmol/mL,25℃,在pH=5~9范围内,甲醛降解率均在90%以上。

一种酞菁锌纳米粒的体外溶出度测定方法的建立与溶出曲线评价

体外溶出是纳米药物重要的质量控制指标,本文对酞菁锌纳米粒的体外溶出进行研究。首先,对比紫外可见和荧光分光光度计对酞菁锌纳米粒中酞菁锌测定的专属性,并建立其标准曲线及进行精密度、回收率实验。之后用透析法测试体外溶出,对比不同溶出介质及取样处理方法对酞菁锌纳米粒中酞菁锌溶出情况的影响并用软件模拟释放模型。结果显示以荧光分光光度计检测时,酞菁锌在0.4~1.9μg·mL^(-1)范围内线性关系良好,相关系数为0.9991。在0.5、1.0、1.5μg·mL^(-1)三个水平下,相对标准偏差(RSD)为1.16~2.32%,精密度良好,且在加样回收实验中回收率为99.40~106.23%。此外,以通常的磷酸缓冲液(PBS)加1%十二烷基硫酸钠(SDS)为溶出介质,将取样冻干后DMF稀释并用荧光分光度计检测。在84 h时,pH 5.0/50μM H_(2)O_(2)组累积溶出可达58.21%。该组体外释放曲线最符合Ritger-peppas方程模型,即药物扩散和骨架溶蚀的共同作用释放机制。

氢化物原子荧光光谱分析中的故障及其排除

阐述了氢化物原子荧光光谱分析中的常见故障及其排除方法。

Recent Progress of the Solar Wind Magnetosphere Ionosphere Link Explorer (SMILE) Mission

The SMILE(Solar wind Magnetosphere Ionosphere Link Explorer)mission is a joint space science mission between the Chinese Academy of Sciences(CAS)and the European Space Agency(ESA),aiming to understand the interaction of the solar wind with the Earth’s magnetosphere in a global manner.As of May 2024,the SMILE mission is in phase-D with an expected launch date of September 2025.This report summarizes developments in the mission during the past two years.

Determination of Chlorogenic Acid,Geniposide,Total Flavonoids and Total Triterpenes in Wulan-13

[Objectives]This study was conducted to establish a method for the determination of chlorogenic acid,geniposide,total flavonoids and total triterpenes in Wulan-13.[Methods]The contents of chlorogenic acid and geniposide were determined by HPLC,and the contents of total flavonoids and total triterpenes were determined by an ultraviolet spectrophotometer.[Results]There was a good linear relation between the mass of chlorogenic acid reference substance and the peak area in the range of 0.05-0.45μg,and the regression equation was Y=2524.1X+3.1943,(r=0.9998).A good linear relationship was found between the mass of gardenoside reference substance and the peak area in the range of 0.776-6.984μg,and the regression equation was Y=1670.5X+64.804,(r=0.9998).There was also a good linear relation between the mass of rutin reference substance and its absorbance in the range of 0.00808-0.04848 mg,and the regression equation was Y=12.916X+0.014,(r=0.999).The mass of oleanolic acid reference substance had a good linear relation with its absorbance in the range of 0.00418-0.0209 mg,and the regression equation was Y=51.89X-0.0839,(r=0.9991).[Conclusions]The content determination method is simple,reliable and reproducible,and suitable for controlling the contents of chlorogenic acid,geniposide,total flavonoids and total triterpenes in Wulan-13.