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HPLC-ICP-MS法分析测定富硒保健品中的硒形态 总被引:1,自引:0,他引:1
确定保健品中硒形态(亚硒酸根、硒酸根),采用水浴振荡提取的前处理方法,液相色谱柱选用IonPac AS11(250 mm×4 mm)分析柱+IonPac AG11(50 mm×4 mm)保护柱,对其进行分离,ICP-MS检测。本文探讨色谱柱、流动相、样品前处理方法的选择,并且在液体、胶囊、鱼油、片状保健品中进行加标回收实验,亚硒酸根、硒酸根的回收率为79.7%-116.4%,精密度(RSD)小于15%。该方法具有灵敏度高、干扰小、样品前处理简单等优点,可以用于保健品中硒形态的筛查和测定。 相似文献
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阿姆河右岸高温、高压、高含硫气田DST测试管柱优化设计 总被引:1,自引:0,他引:1
土库曼斯坦阿姆河右岸高温、高压、高含硫气田的地质结构复杂,具有高压力、低渗透的特点,且天然气中普遍含有H2S、CO2等腐蚀性气体,在测试作业过程中发生过井下测试管柱不密封、油管腐蚀损坏、压力泄露等问题,从而影响施工进度和人员、设备的安全。针对此类问题,从工艺和安全角度出发,本着简单实用的原则,通过对现用的4种DST管柱结构的应用特点及工艺进行分析,优化出一套适用于该区块的DST测试管柱(即射孔—测试—酸化—测试—挤压井管柱),其结构为:TCP管串+RTTS封隔器+安全接头+RD循环阀+RD安全循环阀+OMNI多功能循环阀(不带球)+校深短节+采油树。如果测试后直接投产,则可使用永久式插管封隔器来代替RTTS封隔器,即转换为射孔—酸化—测试—完井管柱。该优化后的管柱设计方案已经成功应用于5口井的测试作业,对指导高温、高压、高含硫井的测试施工设计,有效预防安全质量事故的发生,确保取全、取准地层数据和资料提供了技术支撑。 相似文献
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Jianfeng Wu Cheng Hu Chen Ping Xiaohong Xu Weiheng Xiang 《Ceramics International》2018,44(16):19590-19596
To prolong the service life of cordierite–spodumene composite ceramics applied to the solar heat transmission pipeline, the zircon modifier was introduced to improve the corrosion resistance of the ceramics. The effects of zircon on the density, bending strength, crystalline phase, microstructure and chemical stability were studied. The results showed that the sintering temperature range of the composite ceramics was broadened to 40–60?°C with the introduction of 5–15?wt% zircon. Moreover, the mechanical strength and corrosion resistance of the ceramic materials were improved with the zircon introduction. In particular, sample C3 containing 15?wt% of zircon and sintered at 1360?°C exhibited the best performance, which had the 0.03% Wa, 0.07% Pa, 2.34?g?cm?3 Db and 100.17?MPa bending strength. After acid and alkali corrosion, the water absorption was still less than 0.5% and the strength loss rate decreased to less than 5.3%. The XRD and SEM analyses demonstrated that the ZrSiO4 grains dispersed at the grain boundaries could enhance the mechanical properties. Furthermore, the existence of the Zr4+ ions not only reduced the cationic solubility of the glassy phases but also led to a reaction with OH? to form Zr(OH)4 on the surfaces. This improved the corrosion resistance of the composite ceramics and endowed it with a high residual strength after the acid and alkali corrosion. 相似文献
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Monte Carlo rendering is widely used in the movie industry. Since it is costly to produce noise‐free results directly, Monte Carlo denoising is often applied as a post‐process. Recently, deep learning methods have been successfully leveraged in Monte Carlo denoising. They are able to produce high quality denoised results, even with very low sample rate, e.g. 4 spp (sample per pixel). However, for difficult scene configurations, some details could be blurred in the denoised results. In this paper, we aim at preserving more details from inputs rendered with low spp. We propose a novel denoising pipeline that handles three‐scale features ‐ pixel, sample and path ‐ to preserve sharp details, uses an improved Res2Net feature extractor to reduce the network parameters and a smooth feature attention mechanism to remove low‐frequency splotches. As a result, our method achieves higher denoising quality and preserves better details than the previous methods. 相似文献
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Xiaogang Wu Weiheng Jiang Yu Zhang Wanxin Yu 《International Journal of Communication Systems》2019,32(7)
In this paper, the resource allocation problem for mobile edge computing (MEC) network is discussed. We focus on the design of online resource allocation strategy by considering the time‐varying demands of the combinatorial resources for the mobile users. To handle this issue, at first, a time splitting‐based online allocation mechanism is introduced. Then, for a given resource allocation period of the time splitting, a combinatorial auction mechanism for the combination resources allocation is proposed. We further prove that the proposed combinatorial auction is both individual rational and incentive‐compatible, and which can bring a higher revenue to the service provider. In order to verify the performance of the proposed mechanism, a variable‐relaxed‐based performance‐bound algorithm and a greedy optimization‐based suboptimal algorithm are presented for comparison purpose. Finally, the performance of these proposed algorithms are testified by numerical simulations, which confirm the analysis results. 相似文献