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The linear approximation of the line continuous distri-bution method of singularities is proposed to treat the creeping motion of the arbitrary prolate axisymmetrical body. The analytic expressions in closed form for the flow field are obtained. The numerical results for the proiate spheroid and Cassini oval demonstrate that the convergence and the accuracy of the proposed method are better than the constant density approximation, furthermore, it can be applied to greater slender ratio. In this paper the example is yielded to show that the linear approximation of the singularities for the density on the partitioned segments can be utilized to consider the creeping motion of the arbitrary pointed prolaue axisymmetrical body. 相似文献
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Field measurements of bottom boundary layer processes and sediment resuspension in the Changjiang Estuary 总被引:1,自引:0,他引:1
A field observation of the hydrodynamics and the sediment resuspension in a bottom boundary layer was carried out in the Changjiang Estuary, during July-August 1997. Using bottom field research facilities, detailed measurements of near-bottom currents and suspended sediment concentration distribution within 1.0 m above bed have been obtained in the Changjiang Estuary——a high concentration estuary. An Acoustic Suspended Sediment Monitor (ASSM) wasused to observe near bed sediment resuspension processes. In addition, the log-profile method was applied to estimating hydraulic roughness Z0 and bottom shear stress values (or friction velocities u). Further understanding of sediment suspension mechanics and hydrodynamic characteristics will require the long-term measurements of near bed processes. 相似文献
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Flexible Cu(In,Ga)Se2 Thin-Film Solar Cells on Polyimide Substrate by Low-Temperature Deposition Process 下载免费PDF全文
The electrical and structural properties of polycrystalline Cu(In, Ga)Se2 films grown on polyimide (PI) substrates below 400℃ via one-stage and three-stage co-evaporation process have been investigated by x-ray diffraction spectra (XRD), scanning electron microscopy (SEM) and Hall effect measurement. As shown by XRD spectra, the stoichiometric CIGS films obtained by one-stage process exhibit the characteristic diffraction peaks of the (In0.68Ga0.32)2Se3 and Cu(In0.7Ga0.3)2Se. It is also found that the film structures indicate more columnar and compact than the three-stage process films from SEM images. The stoichiometric CIGS films obtained by three-stage process exhibit the coexistence of the secondary phase of (In0.68Ga0.32)2Se3, Cu2-xSe and Cu(In0.7Ga0.3)2Se. High net carrier concentration and sheet conductivity are also observed for this kind of film, related to the presence of Cu2-xSe phase. As a result, when the CIGS film growth temperature is below 400℃, the three-stage process is inefficient for solar cells. By using the one-stage co-evaporation process, the flexible CIGS solar cell on a PI substrate with the best conversion efficiency of 6.38% is demonstrated (active area 0.16cm^2). 相似文献
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本文考虑了连续奇点线分布法的分段线性近似去处理任意形状长轴对称体的Stokes流动,成功地得到了流场的封闭形式的分析表达式.通过长球和卡西尼卵形体的数值计算表明此法改进了分段等强度近似的收敛性和精度并具有更大的细长比的适用范围.文中还给出实例说明分段线性近似还可用来计算任意形状尖头长轴对称体的Stokes流动. 相似文献
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研究了纳米相氟氧化物玻璃陶瓷中Er~(3+)Yb~(3+)离子对的量子剪裁发光造成的强的光谱调制现象。测量了Er~(3+)Yb~(3+)双掺纳米相氟氧化物玻璃陶瓷的X射线衍射谱、表面形貌、激发光谱、吸收光谱、和发光光谱;而且也与Tb~(3+)Yb~(3+)双掺纳米相氟氧化物玻璃陶瓷的相对应的光谱参数进行了比较。发现378nm光激发样品(A)Er(1%)Yb(8.0%)∶FOV和样品(B)Er(0.5%)Yb(3.0%)∶FOV所导致的652.0nm红色发光强度为522nm光激发时的680.85倍和303.80倍;我们还发现378nm光激发所导致的样品(A)Er(1%)Yb(8.0%)∶FOV和样品(B)Er(0.5%)Yb(3.0%)∶FOV的652.0nm红色发光强度为样品(C)Er(0.5%)∶FOV的491.05和184.12倍。我们还发现在378nm光激发时的样品(A)Er(1%)Yb(8.0%)∶FOV和样品(B)Er(0.5%)Yb(3.0%)∶FOV的{978.0和1 012.0nm}红外发光强度依次分别为样品(C)Er(0.5%)∶FOV的{58.00和293.62}倍和{25.11和67.50}倍。更进一步,对于652.0nm波长发光的激发谱,发现(A)Er(1%)Yb(8.0%)∶FOV和(B)Er(0.5%)Yb(3.0%)∶FOV的378.5nm激发谱峰强度是(C)Er(0.5%)∶FOV的大约606.02和199.83倍。同时,也发现样品(A)Er(1%)Yb(8.0%)∶FOV和样品(B)Er(0.5%)Yb(3.0%)∶FOV的一级量子剪裁红外1 012或978nm发光强度为样品(D)Tb(0.7%)Yb(5.0%)∶FOV的二级量子剪裁红外976nm发光强度的101.38和29.19倍。发现的该量子剪裁是目前所报道的最强的量子剪裁。因此,相信所发现的氟氧化物纳米玻璃陶瓷中Er~(3+)Yb~(3+)离子对的一级量子剪裁发光是强的可以作为量子剪裁层应用到提高晶硅太阳能电池的发电效率。研究结果也能加速对目前国际热点的下一代环保的光谱调制太阳能电池的探索。 相似文献
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以H2S气体作为硫源、固态蒸发硒蒸气作为硒源对电沉积Cu-In-Ga金属预制层进行硒硫化处理. 通过电沉积Cu-In-Ga金属预制层在不同衬底温度下硒化、硫化和硒硫化的对比实验,发现CuInS2相和CuIn(S,Se)2相优先生成,抑制了CuInSe2相的生成,促使InSe相薄膜向内部扩散,减弱了薄膜两相分离现象. 采用先硒化后硒硫化处理工艺优化了Cu(In,Ga)(S,Se)2薄膜的制备工艺,在250 ℃预硒化得到了开路电压为570 mV的太阳电池,在更高的预硒化温度得到了较大短路电流的太阳电池,最终优化得到了效率达到10.4%的电池器件.
关键词:
电化学沉积
Cu-In-Ga金属预制层
硒硫化处理
2薄膜')" href="#">Cu(In,Ga)(S,Se)2薄膜 相似文献
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Cu元素成分对Cu(In,Ga)Se2(简称CIGS)薄膜材料的电学性质及其电池器件性能有很重要的影响.本文利用蒸发法制备了贫Cu和富Cu的CIGS吸收层(0.7Cu/(Ga+In)1.15)及相应的电池器件.扫描电镜和Hall测试发现,富Cu材料的结构特性(晶粒大、结晶状态好)和电学特性(电阻率低、迁移率高等)优于贫Cu材料,而性能测试表明贫Cu器件的效率优于富Cu器件.变温性能测试分析表明,贫Cu器件的主要复合路径是体复合,激活能与CIGS禁带宽度相当;富Cu器件的主要复合路径是界面复合,其激活能远小于CIGS禁带宽度,这大大降低了开路电压Voc,从而降低了电池效率.最后利用蒸发三步法制备了体材料稍富Cu表面贫Cu的CIGS吸收层,降低了短路电流和开路电压的损失,获得了超过15%的电池效率. 相似文献
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