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硫酸铵存在下碘化钾-乙醇体系萃取分离镉 总被引:20,自引:1,他引:20
传统萃取分离法由于采用与水互不相溶的有机溶剂 ,对那些萃取反应速度慢、传质速率低、分配比小的体系需在振荡器上进行较长时间振荡或多次萃取才能达到定量萃取 .均相萃取、异相分离萃取体系由于可以克服异相萃取分离技术中一些缺点而受到重视[1,2 ].本文以乙醇为溶剂 ,均相萃取、异相分离镉 .试验表明 ,硫酸铵存在下 ,乙醇与水分相过程中 ,Cd(Ⅱ )与I- 形成的CdI2 - 4 与质子化乙醇 (C2 H5OH 2 )形成电中性缔合物 (C2 H5OH 2 ) 2 CdI2 - 4 被乙醇相完全萃取 .能使Cd(Ⅱ )从Fe(Ⅲ )、Co(Ⅱ )、Ni(Ⅱ )、Mn(Ⅱ )… 相似文献
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采用甚高频等离子体增强化学气相沉积技术制备了不同衬底温度的微晶硅薄膜.利用傅里叶变换红外吸收对制备薄膜进行了结构方面的测试分析.结果表明:随衬底温度的升高,材料 中的氢含量总的趋势下降;傅里叶变换红外吸收和二次离子质谱测试结果都显示薄膜中氧含 量随衬底温度的升高而增加(在1019cm-3量级);与高衬底温度相 比,低衬底温度制备的材料易于后氧化,这说明低温制备材料的稳定性不好.
关键词:
甚高频等离子体增强化学气相沉积
微晶硅薄膜
傅里叶变换红外吸收 相似文献
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Influence of the total gas flow rate on high rate growth microcrystalline silicon films and solar cells 下载免费PDF全文
This paper reports that high-rate-deposition of microcrystalline
silicon solar cells was performed by very-high-frequency
plasma-enhanced chemical vapor deposition. These solar cells, whose
intrinsic μ c-Si:H layers were prepared by using a different total gas
flow rate (Ftotal), behave much differently in performance,
although their intrinsic layers have similar crystalline volume
fraction, opto-electronic properties and a deposition rate of ~
1.0~nm/s. The influence of Ftotal on the micro-structural
properties was analyzed by Raman and Fourier transformed infrared
measurements. The results showed that the vertical uniformity and
the compact degree of μ c-Si:H thin films were improved with
increasing Ftotal. The variation of the microstructure was
regarded as the main reason for the difference of the J--V
parameters. Combined with optical emission spectroscopy, we
found that the gas temperature plays an important role in
determining the microstructure of thin films. With Ftotal
of 300~sccm, a conversion efficiency of 8.11% has been obtained
for the intrinsic layer deposited at 8.5~\AA/s (1~\AA=0.1\,nm). 相似文献
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Analysis of heating effect on the process of high deposition rate microcrystalline silicon 下载免费PDF全文
A possible heating effect on the process of high deposition rate microcrystalline silicon has been studied.It includes the discharge time-accumulating heating effect,discharge power,inter-electrode distance,and total gas flow rate induced heating effect.It is found that the heating effects mentioned above are in some ways quite similar to and in other ways very different from each other.However,all of them will directly or indirectly cause the increase of the substrate surface temperature during the process of depositing microcrystalline silicon thin films,which will affect the properties of the materials with increasing time.This phenomenon is very serious for the high deposition rate of microcrystalline silicon thin films because of the high input power and the relatively small inter-electrode distance needed.Through analysis of the heating effects occurring in the process of depositing microcrystalline silicon,it is proposed that the discharge power and the heating temperature should be as low as possible,and the total gas flow rate and the inter-electrode distance should be suitable so that device-grade high quality deposition rate microcrystalline silicon thin films can be fabricated. 相似文献
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本文国内首次报道了采用高压RF-PECVD技术沉积本征微晶硅材料的结果.实验表明,增大等离子体激发功率和减小硅烷浓度都能够使薄膜材料由非晶硅逐渐向微晶硅转变,而结构上的改变使得电学特性也随之改变.通过工艺参数的优化和纯化器的使用,有效地控制了氧的掺杂,在较高的生长速度下得到了器件质量级的本征微晶硅材料.将实验得到的微晶硅作为太阳电池光吸收层,在没有ZnO背电极和没有优化窗口层材料以及p/i界面时,电池的效率达到5.22;,这进一步表明本征微晶硅材料的良好性能. 相似文献
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This paper reports that the optical emission spectroscopy (OES) is
used to monitor the plasma during the deposition process of
hydrogenated microcrystalline silicon films in a very high frequency
plasma enhanced chemical vapour deposition system. The OES
intensities (SiH\sj{*}, H微晶硅 VHF-PECVD 发射光谱学 薄膜物理学 microcrystalline silicon,
VHF-PECVD, optical emission spectroscopy 2005-11-09 2005-11-092005-12-12 This paper reports that the optical emission spectroscopy (OES) is used to monitor the plasma during the deposition process of hydrogenated microcrystalline silicon films in a very high frequency plasma enhanced chemical vapour deposition system. The OES intensities (Sill^*, H^* and H^*β) are investigated by varying the deposition parameters. The result shows that the discharge power, silane concentrations and substrate temperature affect the OES intensities. When the discharge power at silane concentration of 4% increases, the OES intensities increase first and then are constant, the intensities increase with the discharge power monotonously at silane concentration of 6%. The SiH^* intensity increases with silane concentration, while the intensities of H^*α and H^*β increase first and then decrease. When the substrate temperature increases, the SiH^* intensity decreases and the intensities of H^*α and H^*β are constant. The correlation between the intensity ratio of IH^*α/ISiH^* and the crystalline volume fraction (Xc) of films is confirmed. 相似文献
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顶空单滴液相微萃取-气相色谱法测定水中苯胺类化合物 总被引:1,自引:0,他引:1
提出了气相色谱法测定水中苯胺、N,N-二甲基苯胺、邻甲苯胺、间甲苯胺等4种苯胺类化合物含量的方法。顶空单滴液相微萃取的优化条件如下:萃取剂为正己烷,萃取温度为25℃,液滴离萃取瓶内液面高度为2.0cm,萃取时间为13min,搅拌速率为400r·min-1。4种苯胺类化合物的质量浓度在0.100~1.00μg·L-1范围内与峰面积呈线性关系,检出限在0.006~0.014μg·L-1之间。方法用于水样分析,加标回收率在90.0%~115%之间,测定值的的相对标准偏差(n=6)均小于10%。 相似文献