High-throughput computational material screening of the cycloalkane-based two-dimensional Dion—Jacobson halide perovskites for optoelectronics

Two-dimensional (2D) layered perovskites have emerged as potential alternates to traditional three-dimensional (3D) analogs to solve the stability issue of perovskite solar cells. In recent years, many efforts have been spent on manipulating the interlayer organic spacing cation to improve the photovoltaic properties of Dion—Jacobson (DJ) perovskites. In this work, a serious of cycloalkane (CA) molecules were selected as the organic spacing cation in 2D DJ perovskites, which can widely manipulate the optoelectronic properties of the DJ perovskites. The underlying relationship between the CA interlayer molecules and the crystal structures, thermodynamic stabilities, and electronic properties of 58 DJ perovskites has been investigated by using automatic high-throughput workflow cooperated with density-functional (DFT) calculations. We found that these CA-based DJ perovskites are all thermodynamic stable. The sizes of the cycloalkane molecules can influence the degree of inorganic framework distortion and further tune the bandgaps with a wide range of 0.9—2.1 eV. These findings indicate the cycloalkane molecules are suitable as spacing cation in 2D DJ perovskites and provide a useful guidance in designing novel 2D DJ perovskites for optoelectronic applications.     

分子印迹TiO2纳米管阵列的制备与选择性光电催化降解邻苯二甲酸二乙酯

以邻苯二甲酸二乙酯(DEP)为模板分子,在TiO2纳米管阵列(TNA)上沉积了能识别DEP分子的TiO2纳米颗粒,制备了DEP分子印迹型TNA(DM-TNA)。X射线衍射(XRD)测试表明,DM-TNA的晶体结构是锐钛矿。扫描电镜(SEM)测试显示颗粒大小约为20 nm的TiO2纳米颗粒均匀地涂覆在TNA的管壁上。光电催化降解DEP和2,4-二氯苯酚(DCP)的结果表明,DM-TNA降解DEP的活性高于非分子印迹TNA(NM-TNA),而DM-TNA降解DCP的活性低于NM-TNA。DM-TNA降解DEP的速率常数是NM-TNA的2.76倍。     

中能重离子碰撞中的各向异性流标度

用同位旋相关的量子分子动力学(IQMD)模型, 研究了25MeV/A的⁸⁶Kr+¹²⁴Sn碰撞系统在较大碰撞参数下的轻碎片的各向异性流(v₂和v₄), 发现横向动量依赖的椭圆流(v₂)存在对轻碎片核子数的标度律(number-of-nucleon scaling)现象, 以及不同轻碎片的v₄/v₂²比值都近似等于一个常数0.5. 这种标度律现象可以用核子层次碎片形成的组合(coalescence)模型来解释.     

Proton Halo or Skin in the Excited States of Light Nuclei

Properties of nuclei 13,15,N and 9B are investigated in the relativistic mean-field theory with NLz and NL3 force parameters.The calculated binding energies are very close to the experimental ones.The calculations show that the first excited state (1p1/2) in 9B,the first excited state (2s1/2)in 13 N and the second excited state(2s1/2) in 15N are weakly bound .In particular,for 13N and 15N,the proton density distributions in the two above excited states have a long tail and the rms radii of the last proton are greatly larger compared with their respective matter radii.It is predicted that a proton halo exists in the first excited state of 13N and in the second excited state of 15N,respectively.It also indicates that the first excited state in 9B is a proton skin state.     

熔合碎裂模型和ALADIN多重碎裂数据

我们用非完全熔合碎裂模型分析了600MeV/u的Au与Cu碰撞后弹剩余核多重碎裂的ALADIN实验结果.由于非完全熔合碎裂模型可以将描述热核形成的动力学和描写热核瞬时多重碎裂的统计模型融为一体,所以只需适当调整与激发能有关的模型参数,就能很好地再现ALADIN数据.     

质子滴线附近的β缓发质子衰变

简要回顾了实验小组在过去8年中获得的实验结果, 即采用氦喷嘴快速带传输系统 +“p-γ”符合方法, 在稀土区质子滴线附近首次观测了9种新核素的β缓发质子衰变, 在A=90核区的N=Z线附近获得了5种核素的β缓发质子衰变的新数据. 并把这14种核素的半衰期, 自旋宇称, 形变以及生成反应截面的实验值与流行的核模型理论预言进行了系统地对比讨论. 从中看出:(1)⁸⁵Mo, ⁹²Rh以及“等待点”核⁸⁹Ru和⁹³Pd半衰期的实验值比近期Moller等人的宏观-微观理论预言值[At. Data Nucl Data Tables, 66, 131(1997)]长5—10倍, 因而明显地影响天体rp过程生成的核素丰度;(2)实验指认的质子滴线核¹⁴²Ho和¹²⁸Pm的自旋宇称与流行理论预言不符, 但用Woods-Saxon-Strutinsky方法可以计算得到相符的位能面;(3)实验估计的9种稀土核的生成截面比通用的Alice和HIVAP程序的计算值要小1—2个数量级.     

A Proposed Reaction Channel for the Synthesis of the Superheavy Nucleus Z=109

We apply a statistical-evaporation model (HIVAP) to calculate the cross sections of superheavy elements, mainly about actinide targets and compare with some available experimental data. A reaction channel ^30Si 4 ^243Am is proposed for the synthesis of the element Z=109 and the cross section is estimated.     

二氧化碳热泵热水器充注量的不动点优化

二氧化碳跨临界循环应用于热泵热水器具有供水温度高、能效高的优点,而最优高压控制是保证其高能效的关键之一。为了避免实际系统最优高压控制的复杂性,提出通过系统设计实现最优充注量近似不变的充注量不动点优化方法,可避免最优高压控制,在保证系统高能效运行的同时极大地简化了系统控制。仿真计算表明,通过调节换热器大小并在气体冷却器出口添加高压储罐,可以使不控高压系统的平均能效衰减减小至-0.8%。     

分子印迹搅拌棒提取-HPLC法测定黄柏中的盐酸小檗碱

以铁丝为磁芯,盐酸小檗碱为目标分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂聚合成分子印迹搅拌棒,并对搅拌棒的制备条件和测定条件进行了选择。用该搅拌棒提取黄柏中的盐酸小檗碱,并用高效液相色谱法进行测定。盐酸小檗碱质量浓度在10~125 mg/L之间与峰面积A呈良好的线性关系,线性回归方程为:A=3.07×103ρ+1.27×106,相关系数r为0.9993,检出限为2.7 mg/L。加样回收率在94.5%~103.5%之间,RSD为3.3%。