Efficient Counter Electrode Manufactured from Ag2S Nanocrystal Ink for Dye‐Sensitized Solar Cells

It is generally believed that silver or silver‐based compounds are not suitable counter electrode (CE) materials for dye‐sensitized solar cells (DSSCs) due to the corrosion of the I^?/I₃^? redox couple in electrolytes. However, Ag₂S has potential applications in DSSCs for catalyzing I₃^? reduction reactions because of its high carrier concentration and tiny solubility product constant. In the present work, CE manufactured from Ag₂S nanocrystals ink exhibited efficient electrocatalytic activity in the reduction of I₃^? to I^? in DSSCs. The DSSC consisting of Ag₂S CE displayed a higher power conversion efficiency of 8.40 % than that of Pt CE (8.11 %). Moreover, the devices also showed the characteristics of fast activity onset, high multiple start/stop capability and good irradiated stability. The simple composition, easy preparation, stable chemical property, and good catalytic performance make the developed Ag₂S CE as a promising alternative to Pt CE in DSSCs.     

Synthesis of Functionalized Mono‐, Bis‐, and Trisethynyltriptycenes for One‐Dimensional Self‐Assembly on Surfaces

This paper describes the synthesis of triptycene‐based building blocks that are able to interact through hydrogen bonds to form one‐dimensional self‐assembled motifs on surfaces. We designed 9,10‐diethynyltriptycene derivatives functionalized at the ethynyl end groups by a variety of hydrogen‐bonding groups for homomolecular recognition and complementary building blocks for heteromolecular recognition. We also present the synthesis of bis‐ and trisethynyltriptycenes with terminal alkyne functional groups available for on‐surface azide–alkyne cycloaddition reaction to expand the potential of the triptycene building block.     

侧链磺化型聚砜质子交换膜的设计与制备及其性能研究

在制备氯甲基化聚砜(CMPSF)的基础上,以对羟基苯磺酸钠(HBSS)和羟基苯二磺酸钠(HBDSS)为亲核试剂,通过亲核取代反应,在聚砜(PSF)主链上分别键联了以苯磺酸根(BSS)和苯二磺酸根(BDSS)基团为末端基的侧链,制得了亲水磺酸根基团与疏水主链"微相分离"结构的2种侧链型磺化聚砜PSF-BSS和PSF-BDSS,并优化了制备条件.在对磺化聚砜产物进行充分表征(FTIR和1H-NMR谱)的基础上,采用流延成膜法制备了质子交换膜,测定了质子交换膜的基本性能,重点考察了质子交换膜"芳香性"主链和亲疏水微区"相分离"这2种结构因素对交换膜性能的影响.实验结果表明,在极性较强的溶剂中,CMPSF与羟基苯磺酸钠可顺利地发生亲核取代反应,于100℃经40 h反应可制得磺酸根键合量分别为2.07 mmol/g和2.11 mmol/g的磺化聚砜PSF-BSS和PSF-BDSS.所制备的质子交换薄膜具有较高的质子传导率(PSF-BDSS交换膜室温为4.7×10-2S/cm,80℃为8.1×10-2S/cm),优良的尺寸稳定性(室温溶胀率为8.6%,80℃溶胀率为30%),且具有良好的热稳定性与抗氧化稳定性.     

聚[(S)-3-乙烯基-2,2'-二羟基-1,1'-联萘]的钛配合物催化三乙基铝对醛的不对称加成反应

通过维蒂希反应合成了(S)-3-乙烯基-2,2'-甲氧甲氧基-1,1'-联萘.将单体(S)-3-乙烯基-2,2'-甲氧甲氧基-1,1'-联萘用偶氮二异丁腈作引发剂进行自由基聚合得到了聚[(S)-3-乙烯基-2,2'-二甲氧基甲氧基-1,1'-联萘].该聚合物上的MOM保护基通过酸脱除获得手性螺旋聚合物聚[(S)-3-乙烯基-2,2'-二羟基-1,1'-联萘].将手性螺旋聚合物聚[(S)-3-乙烯基-2,2'-二羟基-1,1'-联萘]与Ti(O-i-Pr)4形成的配合物应用于三乙基铝与醛的不对称加成反应中,获得了较好的对映选择性,ee值最高为85%.更重要的是,这种聚合物还可以被回收利用多次且催化活性没有明显降低.     

一元强碱滴定一元弱酸溶液的林邦滴定曲线方程及其应用

以林邦副反应思想为基础,用质子条件式PBE、物料平衡式MBE、滴定分数和条件稳定常数等知识推导出一元强碱滴定一元弱酸溶液的林邦滴定曲线方程,并用滴定曲线方程讨论了滴定开始至化学计量点时任意一点p H的计算。     

Redox‐Neutral α‐Allylation of Amines by Combining Palladium Catalysis and Visible‐Light Photoredox Catalysis

An unprecedented α‐allylation of amines was achieved by combining palladium catalysis and visible‐light photoredox catalysis. In this dual catalysis process, the catalytic generation of allyl radical from the corresponding π‐allylpalladium intermediate was achieved without additional metal reducing reagents (redox‐neutral). Various allylation products of amines were obtained in high yields through radical cross‐coupling under mild reaction conditions. Moreover, the transformation was applied to the formal synthesis of 8‐oxoprotoberberine derivatives which show potential anticancer properties.     

考虑破坏时复合材料结构的分析

本文考虑复合材料结构发生局部破坏时的分析问题,这是一个非线性问题。本文引入带步长限制的变步长增量载荷方案作为解决这一问题的工程途径。用有限元法作为结构分析的基本手段。经试验结果对比,初步表明该方案是可行的。     

结构的多机并行分析I——结构的并行有限元方法

本文详细分析和讨论了结构分析的并行有限元方法—并行预处理共轭梯度法(以下简称PPCG法)。着重讨论了基于自带存储器的多处理机系统的并行预处理算法问题,并由此提出了两种PPCG法:PPCG1和PPCG2法。这两种方法适用于以单道剖分(one-way dissection)的子结构法为基础的并行分析。由于这种剖分法产生的结构刚度矩阵具有箭头形状,可独立地消除各子结构的内部自由度,并且不会在刚度矩阵中产生新的非零元素,因此很适合具有较多处理机的并行机系统对复杂结构进行的并行分析。     

翼型与风洞侧壁交接角区分离流动研究

运用Navier-Stokes数值模拟对翼型模型试验时风洞侧壁和翼型模型结合部拐角区黏型分离流动进行模拟,并将简单代数湍流模型扩展用于机翼/风洞侧壁拐角区流动.计算格式在空间上采用中心有限体积离散,在时间上采用多步Runge-Kutta时间步长格式进行积分.结果显示,在翼型模型风洞试验时,模型/侧壁拐角区、模型表面、侧壁表面和模型后形成复杂的黏性分离流动和二次分离,对实验结果产生很大的影响.     

Elastic impact on finite Timoshenko beam

In this paper the analytical solutions of the impact of a particle on Timoshenko beams with four kinds of different boundary conditions are obtained according to Navier's idea, which is further developed. The initial values of the impact forces are exactly determined by the momentum conservation law. The propagation of the longitudinal and transverse waves along the beam, especially, the effects of boundary conditions on the characteristics of the reflected waves, are investigated in detail. Some results are compared with those by MSC/NASTRAN.