Ultrafast Terahertz Probes of Charge Transfer and Recombination Pathway of CH_3NH_3PbI_3 Perovskites

We use transient terahertz photoconductivity measurements to demonstrate that upon optical excitation of CH_3NH_3PbI_3 perovskite, the hole transfer from CH_3NH_3PbI_3 into the organic hole-transporting material(HTM)Spiro-OMe TAD occurs on a sub-picosecond timescale. Second-order recombination is the dominant decay pathway at higher photo-excitation fluences as observed in neat CH_3NH_3PbI_3 films. In contrast, under similar experimental conditions, second-order recombination weakly contributes the relatively slow recombination between the electrons in the perovskite and the injected holes in HTM, as a loss mechanism at the CH_3NH_3PbI_3/Spiro-OMe TAD interface. Our results offer insights into the intrinsic photophysics of CH_3NH_3PbI_3-based perovskites with direct implications for photovoltaic devices and optoelectronic applications.     

Energy Transfer in the Light-Harvesting Complexes of Purple Bacteria

In this paper, we use a nonlinear decohering quantum model to study the initial step of photosynthesis which is an ultrafast transfer process of absorption the sunlight by light-harvesting complexes and electronic excitation transfer to the reaction center(RC). In this decohering model, the Hamiltonian of the system commutes with the systemenvironment interaction. We take B850 ring of light-harvesting complex II(LH-II) in purple bacteria as an example to calculate the efficiency of the energy transfer as a function of time. We find that the environmental noise can make the LH-II have stable energy transfer efficiency over a long time. This is to say that the environmental noise which is the decohering source has advantage of the energy transfer in the process of photosynthesis.     

焦粉基碳吸附材料对铜(Ⅱ)离子吸附特性

采用硝酸预氧化焦粉、氯化锌化学活化法制备了焦粉基碳吸附材料。 考察了焦粉基碳吸附材料对水中铜(Ⅱ)离子的吸附特性。 实验结果表明,焦粉基碳吸附材料吸附平衡时间90 min,该吸附过程符合Langmuir型吸附模型;不同温度下的ΔHθ＞0、ΔGθ＜0,证实其吸附过程是一个自发吸热过程;ΔSθ＞0,表明铜离子在固液界面有序性减小、混乱度增大。 对实验数据进行数学模型拟合,二级相关系数R2=0.999 1,显示吸附过程动力学与二级动力学模型相关性较好。     

HKC细胞损伤前后对草酸钙晶体吞噬能力的差异

采用人类肾脏近端小管上皮细胞系(HKC)建立氧化性损伤模型,研究损伤前后HKC调控草酸钙(CaOxa)结晶的差异。采用CCK-8法检测HKC的细胞活性;利用激光共聚焦显微镜观察HKC损伤后表达的晶体粘附分子骨桥蛋白(OPN);采用倒置显微镜观察HKC的形态变化;采用扫描电子显微镜(SEM)观察HKC微结构及其诱导的晶体;采用X射线衍射分析(XRD)表征晶体的组分。在CaOxa过饱和溶液中,正常HKC主要诱导形成二水草酸钙(COD)晶体,而损伤HKC则同时诱导了COD和一水草酸钙(COM)晶体。正常HKC对COD晶体有较强的吞噬能力,而损伤HKC的这种能力较弱;HKC损伤后表达OPN,促进CaOxa晶体的成核和聚集,从而增加了肾结石形成的危险性。     

不同晶相草酸钙超细微晶的合成及其与硫酸软骨素A的相互作用

采用配位沉淀法制备了二水草酸钙(COD)和一水草酸钙(COM)超细微晶,其尺寸分别为150nm和320nm。通过扫描电子显微镜(SEM)、X射线衍射(XRD)、红外光谱(FTIR)、纳米粒度仪(Nano-ZS)和紫外-可见吸收光谱(UV-Vis)表征了这两种草酸钙微晶。研究了尿大分子硫酸软骨素A(C4S)对上述COM和COD微晶ξ电位、粒径、聚集程度和紫外吸光度的影响。随着cC4S从0增加到1.0g·L-1,COD微晶的ξ电位从-9.7mV减小到-46.1mV,COM微晶的ξ电位从-15.9mV减小到-49.0mV;微晶表面ξ电位变负后,有利于稳定溶液中悬浮的微晶。在水溶液中,COD和COM微晶均存在显著的聚集现象,而C4S的存在可抑制COD微晶的聚集,并在浓度为0.05g·L-1时抑制效果最好。由于尿液中存在大量草酸钙微晶,本研究有助于阐明草酸钙结石的形成机理和C4S对草酸钙结石形成的抑制作用。     

基于胶束插层方法制备高热稳定性和大层间距有机化蒙脱土

采用不同方法制备了多种有机化蒙脱土,并分别采用X射线衍射仪、红外光谱分析仪、热重分析仪、电感耦合等离子体发射光谱仪、元素分析仪、扫描电子显微镜对产物进行了表征,并提出了有机物插层新方式——胶束插层.结果表明:适量钠基蒙脱土(Na-MMT)、十六烷基三甲基溴化铵(CTAB)和磷酸三苯酯(TPP)在丙酮/水的混合溶剂中进行溶液插层,得到的有机化蒙脱土具有更大的层间距,比单纯采用CTAB的插层效果显著.产物中含有约21.54%的CTAB和17.47±1.05%的TPP,插层机理为CTAB-TPP胶束插层.该有机化蒙脱土的初始热降解温度比单纯CTAB插层蒙脱土最多提高了17.4℃.采用该方法制备的改性蒙脱土既可以进一步提高蒙脱土的层间距,又可以封闭TPP于MMT的片层间,阻止TPP挥发;同时克服季铵盐改性蒙脱土的热稳定性低的问题,得到了层间距大、热稳定性高的有机化蒙脱土,为有机化蒙脱土在高熔点聚合物改性方面提供了条件.     

胸腔积液中低分子量蛋白质的提取

胸腔积液的生化指标已经成为临床疾病诊断的重要依据.引起胸腔积液的疾病中,人们最为关注的是恶性肿瘤引起的胸水渗漏(恶性胸水),并且做了比较系统的研究~([1,2]).在胸腔积液中寻找蛋白模式的肿瘤标志物越米越得到人们的重视.与血清相似,胸腔积液中白蛋白也干扰其它低丰度蛋白的检测.本研究建立一种简单的圆盘电泳方法,提取胸腔积液中低分子量蚩白,去除高分子量蛋白,包括人血白蛋白.     

Structural and optical properties of Al1-xInxN epilayers on GaN template grown by metalorganic chemical vapor deposition

This paper reports that Al1 xInxN epilayers were grown on GaN template by metalorganic chemical vapor de-position with an In content of 7%-20%. X-ray diffraction results indicate that all these Al1 xInxN epilayers have a relatively low density of threading dislocations. Rutherford backscattering/channeling measurements provide the exact compositional information and show that a gradual variation in composition of the Al1 xInxN epilayer happens along the growth direction. The experimental results of optical reflection clearly show the bandgap energies of Al1 xInxN epilayers. A bowing parameter of 6.5 eV is obtained from the compositional dependence of the energy gap. The cathodoluminescence peak energy of the Al1 xInxN epilayer is much lower than its bandgap, indicating a relatively large Stokes shift in the Al1 xInxN sample.