镨掺杂分布对1.3μm光纤放大器特性影响

对掺氟化镨玻璃光纤放大器的小信号增益，用广义的高斯近似公式可获得精确的分析表达。文中研究了限制光纤芯层中央部分的镨掺杂对光纤放大器特性的影响，结果发现限制镨掺杂分布能改进光纤放大器的工作效率，且截止波长比芯层全部均匀掺镨的光纤更长。     

钽铌冶炼厂酸性含氟废水处理试验研究

用单纯的石灰中和沉淀法处理高浓度酸性含氟废水很难达到排放标准(≤10mg·L-1)。试验采用两步中和沉淀法处理稀土冶炼产生的酸性高氟废水,即分两次投加石灰乳,并用PAM作为混凝剂。结果表明,采用该工艺处理后的出水含氟量低于5mg·L-1,重金属离子含量也可达到排放标准,同时可提高石灰的利用率和改善处理效果。     

免疫亲和柱净化-柱后衍生高效液相色谱荧光法快速检测玉米粉中黄曲霉毒素B1

本文建立了免疫亲和柱净化-高效液相色谱荧光法-陕速检测玉米粉中黄曲霉毒素B1（aflatoxin B1,AFB1）的方法。样品经甲醇/水（4∶1.v/v）浸提,免疫亲和柱净化,高效液相色谱分离,光化学柱后衍生,荧光检测器测定。结果表明：AFB1在2.5-150μg/L具有良好的线性关系,相关系数为R-2=0.9998,检测限为1.0μg/kg,平均回收率为84.0%-96.3%,RSD范围为0.7%-2.5%。该方法具有快速、准确和重复性好的优点,适用于大批次玉米及玉米粉制品中AFB1的检测。     

Synthesis and Characterization of Arsenate/Phosphate Fluorapatite Solid Solutions

A series of arsenate-substituted fluorapatite (FA) was directly prepared through the aqueous precipitation method. Characterization studies from elemental analysis, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, and scanning electron microscopy (SEM) have confirmed the formation of the arsenate/phosphate fluorapatite solid solutions (AsPFAs), i.e., Ca₅(P _x As_1–x O₄)₃F, which had a single phase of apatite structure. The analysis of the measurements indicated that the unit cell a and c parameters did not vary smoothly with the degree of substitution, as expected by Vegard’s law. The morphology was dependent of the arsenate/phosphate ratio. The solids with high As/(P + As) molar ratio of 0.29 to 1.0 were typically needlelike crystals, which developed along the c-axis; all apatites with the As/(P + As) molar ratio of <0.09 were large tabular. The phosphate peaks and the arsenate peaks in the FT-IR spectra were observed for the entire series of substituted apatites. The area of the phosphate peak was gradually suppressed and that of the arsenate peak increased as the proportion of the arsenate increased.     

The Hydrogeochemistry of Arsenic in the Clara Mine,Germany

Abstract.   The oxidative dissolution of primary arsenic-bearing sulfide minerals in barite-fluorite veins is a potential source of arsenic in the Clara Mine. Geological structures, especially the mineral veins, provide potential pathways for the water. The highest arsenic concentrations are found in ground water within the eastern part of the mine. Arsenic and major ions are positively correlated and provide evidence that arsenic is likely derived locally from the water-vein/water-rock interaction. Geochemical modeling with PHREEQC shows all the arsenate mineral phases to be significantly undersaturated, although secondary arsenate minerals are common in the oxidized part of the deposit. The mine waters plot near the boundary of Fe(OH)₃ and Fe²⁺ in the pH-Eh diagram for the As-Fe-S-H₂O-system. Arsenic occurs as the 5-valent species and . Statistical analysis illustrates a strong association between As, Fe, pH, and HCO₃. Oxidation of the primary As-bearing minerals, such as pyrite and arsenopyrite, and the subsequent behavior of the oxyanion, arsenate, generally controls the distribution and speciation of arsenic. The low concentrations of dissolved As is due to co-precipitation and adsorption of arsenate by Fe, Al, and Mn (oxy)hydroxides.     

柘城地区浅层地下水化学类型与高氟水成因分析

以柘城地区浅层地下水化学特征及水中氟离子质量浓度为研究对象,开展地形地貌、水文地质及环境地质调查、水样测试等工作,分析研究区地下水化学类型、气象、岩性、水化学成分。结果表明,岩石、土壤是研究区高氟地下水形成的主要因素,同时气候、地貌和水文地质条件也对研究区高氟地下水的形成产生影响。     

全视频智慧停车场综合解决方案

针对传统停车场管理的多种弊端,提出了全视频智慧停车场综合解决方案,介绍了出入口的视频免取卡收费系统、停车场内车位引导系统及反向查询(找车)系统。综合解决方案为车主提供了一种更加安全、舒适、方便、快捷和开放的停车环境,同时提高了停车场的信息化、智能化管理水平。     

废旧塑料的热裂解技术

介绍了当前国内外几种处理和利用废旧塑料的方法，特别对废旧塑料热裂解制造燃烧油和化学品的技术、工艺流程和存在的问题作了重点探讨。     

MYF型连铸机用中间包的流场测试和优化的水模研究

对ＭＹＦ型四流中间包的水模流动测试表明：包内各流股的流动特性值在较大的差异，对浇铸构成不利的影响。控流后，明显改善了中间包的流场条件，为现场提供了中间包控流的依据和方案。     

Potential of Leersia hexandra Swartz for phytoextraction of Cr from soil

Research on the phytoextraction of Cr from contaminated soils has been scarce, because very few plant species have been reported to accumulate Cr to high concentrations in their aerial parts. In this study, a Cr-hyperaccumulator, Leersia hexandra was investigated for its potential to remove Cr from the soil in a series of pot experiments. The results showed that L. hexandra had a high extraction capacity for chromium in soil, with the highest Cr concentration in shoot of 1844 mg/kg. Model calculation based on the negative linear relationship between the bioconcentration factors (BCF) and the concentrations of soil Cr indicated that phytoremediation using L. hexandra was feasible when soil was only moderately contaminated with Cr. Three sequential harvests did not significantly alter Cr accumulation and shoot biomass (p > 0.05), indicating that sequential harvest might be an available and convenient way to achieve the decontamination of Cr-contaminated soils by L. hexandra. On average, fertilization increased the shoot biomass by 45% and the total amount of extracted-Cr by 26%, suggesting that fertilization is able to enhance Cr phytoextraction of L. hexandra. Although EDTA increased the concentrations of Cr in shoots by 1.4 times, it also resulted in low plant biomass, thereby decreasing the amount of Cr accumulation.