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981.
Odlyha M. Cohen N. S. Campana R. Foster G. M. 《Journal of Thermal Analysis and Calorimetry》1999,56(3):1219-1232
This paper describes the results and conclusions of research directed towards the development and evaluation of a chemical
sensor which would provide information on the quality of indoor environments surrounding cultural objects. In our case these
objects were paintings housed in major European galleries and the main objective is their preservation through an improved
understanding of their microenvironment. The concept was to prepare and expose test tempera paintings which would behave as
dosimeters and integrate the environmental response at these locations. Artificial ageing of similar samples was performed
to provide a means of calibrating the test paintings. Samples from the test paintings were compared with artificially aged
samples and this enabled the sites to be ranked in terms of their suitability for exposure of cultural objects.
Additionally, novel methodology involving piezoelectric sensors was designed for monitoring the relative humidity and temperature
of the microenvironment of paintings. Dielectric techniques were also used for measuring the effect of relative humidity fluctuations
on artists' materials and novel non-invasive dielectric techniques in the microwave region were used for the determination
of their moisture content.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
982.
983.
通过水热结合高温退火的方法制备了一种Ni-Mn双金属氧化物微马达,所得Ni-Mn双金属氧化物具有针刺状空心结构,可作为马达材料。该Ni-Mn双金属氧化物微马达在燃料(H2O2)质量分数仅为1%时显示出很强的驱动能力,运动速度为83.75μm·s-1,寿命高于90 min。即使在H2O2质量分数低至0.4%时,该马达仍具有优异的自主运动。由于镍氧化物的存在,该马达可通过磁场控制实现定向运动。得益于优异的催化性能和磁性,该Ni6MnO8马达可在160 s内有效去除亚甲基蓝,且没有二次污染。 相似文献
984.
以苏南的张家港市,苏中的如东县,苏北的涟水县2000年的土地利用现状数据和2010年的土地规划数据为基础,从自然、社会经济和生态三方面结合三个市县的环境特点,构建土地开发整理规划环境影响评价指标体系,按照层次分析法(AHP)确定各因子权重,应用模糊综合评判法,综合评价土地开发整理规划对环境的影响。研究结果表明:土地整理规划有助于区域综合环境的改善,且发展越快的地方其环境综合效应提升也越快。 相似文献
985.
Ray L. Frost 《Journal of Raman spectroscopy : JRS》2011,42(5):1130-1134
Raman spectroscopy has been used to study selected mineral samples of the copiapite group. Copiapite (Fe2+Fe3+(SO4)6(OH)2 · 20H2O) is a secondary mineral formed through the oxidation of pyrite. Minerals of the copiapite group have the general formula AFe4(SO4)6(OH)2 · 20H2O, where A has a + 2 charge and can be either magnesium, iron, copper, calcium and/or zinc. The formula can also be B2/3Fe4(SO4)6(OH)2 · 20H2O, where B has a + 3 charge and may be either aluminium or iron. For each mineral, two Raman bands are observed at around 992 and 1029 cm−1, assigned to the (SO4)2−ν1 symmetric stretching mode. The observation of two bands provides evidence for the existence of two non‐equivalent sulfate anions in the mineral structure. Three Raman bands at 1112, 1142 and 1161 cm−1 are observed in the Raman spectrum of copiapites, indicating a reduction of symmetry of the sulfate anion in the copiapite structure. This reduction in symmetry is supported by multiple bands in the ν2 and ν4(SO4)2− spectral regions. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
986.
斜梁在热作用下的动力特性 总被引:1,自引:2,他引:1
根据弹性稳定理论及Galerkin原理研究了斜梁在热状态下的动力特性问题,并讨论分析了温度、长细比、梁截面形式、倾斜角、荷栽、阻尼力对斜梁动力稳定性的影响,研究表明,在热效应下杆件的倾角、长细比、梁截面形式、振动荷载对斜梁的动力特性影响较大,而杆件的阻尼力则影响较小,可忽略不计.并提出在实际工程中如何减小振动的相关措施,可供工程结构动力分析与设计参考. 相似文献
987.
几种水环境质量综合评价方法的探讨 总被引:24,自引:0,他引:24
朱静平 《西南科技大学学报》2002,17(4):62-67
根据对涪江水体某断面监测得到的具体数据,利用各种评价方法进行了水质评价,并对评价结果作了相应比较,进而提出了适于对水环境质量进行综合评价的评价方法。 相似文献
988.
选取济南市1994-2003年经济与环境数据,建立单位GDP污染排放量模型和人均GDP污染排放量模型,分析工业“三废”与人均GDP增长的环境库兹涅茨曲线(EKC)。从模型模拟结果看,单位GDP污染排放量总体呈现下降趋势,表明济南市产业结构在十几年的演变过程中发生了明显的变化。发现济南市经济发展与环境污染水平的关系总体上符合EKC特征;济南市经济目前仍处于工业化进程的中期阶段,环境污染物排放量EKC的转折点尚未达到。 相似文献
989.
《Journal of separation science》2018,41(7):1618-1624
This work presents a new extraction material, namely, Q‐100, based on hypercrosslinked magnetic particles, which was tested in dispersive solid‐phase extraction for a group of sweeteners from environmental samples. The hypercrosslinked Q‐100 magnetic particles had the advantage of suitable pore size distribution and high surface area, and showed good retention behavior toward sweeteners. Different dispersive solid‐phase extraction parameters such as amount of magnetic particles or extraction time were optimized. Under optimum conditions, Q‐100 showed suitable apparent recovery, ranging in the case of river water sample from 21 to 88% for all the sweeteners, except for alitame (12%). The validated method based on dispersive solid‐phase extraction using Q‐100 followed by liquid chromatography with tandem mass spectrometry provided good linearity and limits of quantification between 0.01 and 0.1 μg/L. The method was applied to analyze samples from river water and effluent wastewater, and four sweeteners (acesulfame, saccharin, cyclamate, and sucralose) were found in both types of sample. 相似文献
990.