Electronic structures and magnetic properties in Cu-doped two-dimensional dichalcogenides

We explore the electronic structures and magnetic properties in Cu-doped MX₂ (=MoS₂, MoSe₂, MoTe₂, and WS₂) based on density functional theory. A Cu dopant leads to a net moment of 5.0 or 1.0 μ_B in MX₂, which mainly depend on the size of crystal-field splitting relative to that of the spin splitting. No magnetism is observed in Cu-doped MoTe₂. The local distortion around the Cu atom reduces the total magnetic moment in two-Cu-doped MX₂. The magnetic coupling between the nearest neighboring Cu atoms is ferromagnetic for all the cases, but they demonstrate various magnetic ground states with the increasing distance between Cu atoms: the Cu-doped MoS₂ and WS₂ exhibit anti-ferromagnetic and nonmagnetic ground state, respectively. A long-range ferromagnetic or ferrimagnetic coupling is attributed to double-exchange interaction in Cu-doped MoSe₂. Half-metallic ferromagnetism with Curie temperature above room temperature in Cu-doped MoSe₂ provides a useful guidance to engineer the magnetic properties of MoSe₂ in experiments.     

Hierarchical self-assembly of 3D amphiphilic discrete organoplatinum(Ⅱ)metallacage in water

Here we described the design and synthesis of a discrete 3D amphiphilic metallacage 4,in which the tetragonal prismatic frameworks act as the hydrophobic cores and the poly(ethylene glycol)(PEG)chains as the hydrophilic tails.The structure of 4 was characterized by 1H NMR,31P NMR and electrospray ionization time-of-flight mass spectrometry(ESI-TOF-MS).Notably,4 with its Iong PEG tails was subsequently ordered into micelles at a low concentration(1.20×10^-6 mol/L)in water.As the concentration and cultivation time increased,the micelles can further self-assembly into nanofibers and nanoribbons.Considering the dynamic property of the coordination bond,these structures show reversible transformation under external stimuli.     

Comparison of Two Rhodamine-Polyamine Polystyrene Solid-phase Fluorescence Sensors for Hg(II) Detection Based on Theoretical Calculation

Two novel rhodamine-based polystyrene solid-phase fluorescence sensors PS-PA-I and PS-PA-II with different lengths of polyamines were synthesized for Hg(II) determination. The detection mechanism involving the Hg(II) chelation-induced spirocycle open of rhodamine was proposed with the aid of theoretical calculation. The stronger N-Hg bond and the longer polyamine chain in PS-PA-II led to a better selectivity, much higher and more quickly fluorescence response to Hg(II).     

外场目标特性测试精度标定及改进方法

针对外场目标特性测试的特点．对其测量原理进行了分析．结合靶场实际．讨论了其定标校方法和提高测量精度的途径。旨在提高目标特性测试的科学性、准确性和可靠性。     

The Impact of Foaming Effect on the Physical and Mechanical Properties of Foam Glasses with Molecular-Level Insights

Foaming effect strongly impacts the physical and mechanical properties of foam glass materials, but an understanding of its mechanism especially at the molecular level is still limited. In this study, the foaming effects of dextrin, a mixture of dextrin and carbon, and different carbon allotropes are investigated with respect to surface morphology as well as physical and mechanical properties, in which 1 wt.% carbon black is identified as an optimal choice for a well-balanced material property. More importantly, the different foaming effects are elucidated by all-atomistic molecular dynamics simulations with molecular-level insights into the structure–property relationships. The results show that smaller pores and more uniform pore structure benefit the mechanical properties of the foam glass samples. The foam glass samples show excellent chemical and thermal stability with 1 wt.% carbon as the foaming agent. Furthermore, the foaming effects of CaSO₄ and Na₂HPO₄ are investigated, which both create more uniform pore structures. This work may inspire more systematic approaches to control foaming effect for customized engineering needs by establishing molecular-level structure–property–process relationships, thereby, leading to efficient production of foam glass materials with desired foaming effects.     

酰胺功能化修饰琼脂糖/硅胶复合材料的制备及吸附性能研究

采用溶胶-凝胶法,以氧化琼脂糖和四甲氧基硅烷为前驱体,通过水解、缩聚反应制得琼脂糖/硅胶复合材料,进一步利用开环、"巯-烯"点击和酰胺化反应对复合材料实现酰胺基团功能化修饰.借助红外光谱(FT-IR)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)对所制备复合材料进行结构、组成和微观形貌表征.以制备的酰胺功能化修饰琼脂糖/硅胶复合材料为吸附剂,探讨其对莱克多巴胺的吸附过程,实验考察了溶剂、吸附时间、莱克多巴胺的初始浓度等对吸附的影响.结果表明:经过修饰反应酰胺基团成功接枝到琼脂糖/硅胶复合材料,该材料颗粒呈球形,粒径在2～3μm之间;复合材料对莱克多巴胺表现出良好的吸附性能,吸附过程50 min达到平衡,适合准二级动力学特征,属化学吸附,吸附等温线符合Freundlich模型;复合材料经过6次吸附解析,再生后对莱克多巴胺的吸附率仅有小幅下降,表明具有较好的循环再生吸附能力.     

玻色化方法在超对称可积系统的应用

利用玻色化方法可以避免超对称可积系统中反对易费米场带来的计算困难. 本文以N=1超对称mKdVB系统为例, 利用玻色化方法, 将其转化为只有玻色场的耦合系统. 应用标准的WTC方法, 证明了该耦合系统具有Painlevé性质. 运用Painlevé截断方法, 可以得到玻色化后超对称mKdVB系统的非局域对称. 为了求解与非局域对称相关的Lie第一性原理, 引入新的场将玻色化后系统拓展为更大的系统. 通过引入新的场, 该非局域对称局域化为Lie点对称. 因此, 可以利用Lie点对称约化方法研究拓展后的系统, 得到超对称mKdVB系统的孤子与其他孤波相互作用解.     

改进的五阶WENO-Z+格式

WENO-ZWENO-Z$+\!$格式的性能提升依赖于新增项的作用,该项的作用是在WENO-Z格式的基础上进一步增大欠光滑子模板上的权重. 系数$\lambda$被设置用来调控该项的作用, 以避免负耗散. 本文指出了WENO-Z$+\!$格式的缺陷,其所采用$\lambda $的取值方式既不能充分发挥格式的潜力, 也未完全消除负耗散;提出$\lambda $的值应随当地流场数据变化,方能充分发挥新增项在降低数值耗散、提高分辨率上的潜力. 基于此,本文重新设计了$\lambda $的计算公式,该公式能自适应地调控新增项的作用: 只在欠光滑子模板上的权重容易过度增大的地方削弱该项的作用,以避免负耗散; 在其他地方则充分发挥新增项的作用,最大限度增大欠光滑子模板上的权重, 提高格式的分辨率.将使用该系数公式的新格式命名为WENO-Z++, 并对其数值性能进行了系统的研究.理论分析表明, 新格式在间断处具有基本无振荡(essentially non-oscillatory,ENO)特性和更低的数值耗散. 对近似色散关系(approximate dispersion relation,ADR)的研究表明,新格式有效地避免了因过度增大欠光滑子模板上的权重而带来的负耗散,其频谱特性也得到了显著提升.本文还推导了使新格式在极值点处也能保持最优阶的精度的参数设置.一系列求解Euler方程的数值试验表明,新格式的激波捕捉能力和对复杂流场结构的分辨率都显著优于原WENO-Z$+\!$格式.}     

Syntheses, Crystal Structures and Fluorescence Properties of Two Triazolyl Derivatives with Biphenyl Links

Two novel triazolyl derivatives with biphenyl links, namely 4,4-bis（1,2,4-triazol-1-ylmethyl）biphenylene 1 and 4,4-bis（3,5-dimethyl-1,2,4-triazol-1-ylmethyl）biphenylene 2, have been synthesized and structurally characterized by single-crystal X-ray diffraction. Compounds 1·H2O·HCl and 2·2H2O·2HCl crystallize in the monoclinic system with space group C2/c and P21/c, respectively. The dihedral angles of the two phenyl rings are 30.26（6）° in 1·H2O·HCl, while co-planar （0.00（7）°） in 2·2H2O·2HCl. In 1·H2O·HCl, the N-H…O hydrogen bonds link 1 to form chain-like structures which are further connected by O-H…Cl, C-H…Cl, C-H…O and π-π supramolecular interactions. The hydrogen bonds of O-H…Cl in 2·2H2O·2HCl provide distinguishing P/M helical chains along the b axis, and these chains are further connected by N-H…O hydrogen bonds to generate a 2D structure. Compounds 1 and 2 in methanol solution show much stronger emission bands at 319 nm than biphenyl at 316 nm under excitation at 260 nm.     

一类[Os^（Ⅱ）（CO）3（tfa）（L）]（L=O^O，O^N，N^N）配合物的结构和光谱特征

采用密度泛函理论以及B3LYP方法和单激发组态相互作用(CIS)方法分别优化了一系列[Os(II)(CO)3(tfa)(L)](tfa为三氟乙酸;L=O^O(1),O^N(2),N^N(3),其中O^O为六氟乙酰丙酮,O^N为羟基喹啉,N^N为3-(三氟甲基)-5-(2-吡啶基)吡唑)配合物的基态和激发态结构.利用含时密度泛函理论(TD-DFT)结合极化连续溶剂化模型(PCM)计算了配合物在CH2Cl2溶液中的吸收和发射光谱.研究结果表明,优化得到的几何结构参数和相应的实验值符合得非常好,激发态几何构型相对基态变化较小,这与实验上观察到的较小的斯托克斯频移现象一致.配合物1-3的最低能吸收分别在342、431和329nm,其磷光发射分别在521、638和488nm.配合物1-3的最高占据分子轨道和最低空轨道主要表现为L配体的π和π*轨道特征,所以它们的最低能吸收归属于π-π*电荷跃迁,并混有少量的金属到配体的电荷跃迁(MLCT)和配体之间电荷跃迁(LLCT)微扰,且其高能吸收也表现为配体内部(IL)和配体间(LL)的电荷跃迁.此外,它们的磷光发射和吸收有相似的跃迁特征.