OCS分子在128 nm附近的光解动力学研究：S(3PJ=2,1,0)、S(1D2)以及S(1S0)产物通道

本文利用时间切片离子成像技术对OCS分子进行了真空紫外波段的光解动力学研究. 在四个光解光波长(从129.32到126.08 nm)下测量了硫原子解离产物S(³P_J=2,1,0)、S(¹D₂)、S(¹S₀)的速度影像,并从中清晰地发现了四个主要的解离产物通道：S(³P_J=2,1,0)+CO(X¹Σ⁺),S(³P_J=2,1,0)+CO(A³π),S(¹D₂)+CO(X¹Σ⁺)和S(¹S₀)+CO(X¹Σ⁺). 在实验影像中,产物CO分子的部分振动态结构能够得到分辨. 实验还获取解离产物总平动能谱,产物分支比和角分布. 对实验结果进行分析显示除绝热解离通道S(³P_J=2,1,0)+CO(A³π)之外,在其他三个产物通道中非绝热效应都起到非常重要的作用.     

OCS经由F 31Π里德堡态生成CO(X1Σ+)+S(1D2)产物的波长相关性光解离

本文利用时间切片离子速度成像技术在134∽140 nm波段研究了OCS分子经由F 3¹Π里德堡态的真空紫外光解离动力学. 在选取的5个分别对应OCS(F 3¹Π, v₁=0∽4)的伸缩振动激发的光解波长,实验测得了来自CO(X¹Σ⁺)+S(¹D₂)产物通道的SS(¹D₂))实验影像,并获得了总平动能谱和CO(X¹Σ⁺, v)共生产物的振动布居及角分布. 结果分析表明OCS分子解离生成CO(X¹Σ⁺)+S(¹D₂)产物的过程经历了上态F 3¹Π 与C_?v和C_s构型的下电子态间非绝热耦合过程. 实验结果显示了很强的波长相关性：OCS (F 3¹Π, v₁)的较低转动激发态(v₁=0∽2)和较高转动激发态(v₁=3, 4)的CO(X¹Σ⁺)产物的振动布居和角分布具有显著差异,表明该解离过程中具有不同的解离机理. 本结果提供了振动耦合可能对真空紫外光解离动力学产生关键作用的相关证据.     

Metal ion capacitor composed of the thin-walled surfaces enabling high-rate performance and long cycling stability

Electrochemical capacitors (referred to as supercapacitors) have high power density, long cycling stability, and are eco-friendly for use in electronic applications. The proper and stable utilization of supercapacitor systems can expand the practical scope of energy-powering applications in various device platforms. Nevertheless, the low energy density of conventional oxide and sulfide electrode materials still limits the practical realization of supercapacitor devices in real electronic applications. This limitation results from the poor surface stability, structural collapse, and low electrical conductivity of the oxide and sulfide materials. Single metal electrodes with multivalent metal ions exhibit promising energy-storing kinetics and may be viable alternatives to these oxide and sulfide electrode materials. Here, we report a metal zinc (Zn) electrode supercapacitor (ZIC) consisting of a thin-walled architecture as an electrode by means of a voltage-controlled electroplating method. The optimized ZIC exhibited excellent pseudo-capacitive performance, excellent high-rate performance, and an outstanding cycling stability.     

Nucleon effective mass splitting and density-dependent symmetry energy effects on elliptic flow in heavy ion collisions at E_(lab)= 0.09 ～ 1.5 GeV/nucleon

By incorporating an iso spin-dependent form of the momentum-dependent potential in the ultra-relativistic quantum molecular dynamics(UrQMD) model,we systematically investigate effects of the neutron-proton effective mass splitting m*_(n-p)=m*_n-m*_p/m and the density-dependent nuclear symmetry energy E_(sym)(ρ) on the elliptic flow v_2 in~(197)Au+~(197) Au collisions at beam energies from 0.09 to 1.5 GeV/nucleon.It is found that at higher beam energies(≥0.25 GeV/nucleon) with the approximately 75 MeV difference in slopes of the two different E_(sym)(ρ),and the variation of m*_(n-p) ranging from-0.03 to 0.03 at saturation density with isospin asymmetry δ=(ρ_n-ρ_p)/ρ-0.2,the E_(sym)(ρ) has a stronger influence on the difference in v_2 between neutrons and protons,i.e.,v_2~n-v_2~p,than m*_(n-p) has.Meanwhile,at lower beam energies(≤0.25 GeV/nucleon),v_2~n-v_2~p is sensitive to both the E_(sym)(ρ) and the m*_(n-p).Moreover,the influence of m*_(n-p) on v_2~n-v_2~p is more evident with the parameters of this study when using the soft,rather than stiff,symmetry energy.     

Probe chiral magnetic effect with signed balance function

In this paper a pair of observables are proposed as alternative ways,by examining the fluctuation of net momentum-ordering of charged pairs,to study the charge separation induced by the Chiral Magnetic Effect(CME)in relativistic heavy ion collisions.They are,the out-of-plane to in-plane ratio of fluctuation of the difference between signed balance functions measured in pair’s rest frame,and the ratio of it to similar measurement made in the laboratory frame.Both observables have been studied with simulations including flow-related backgrounds,and for the first time,backgrounds that are related to resonance's global spin alignment.The two observables have similar positive responses to signal,and opposite,limited responses to identifiable backgrounds arising from resonance flow and spin alignment.Both observables have also been tested with two realistic models,namely,a multi-phase transport(AMPT)model and the anomalous-viscous fluid dynamics(AVFD)model.These two observables,when cross examined,will provide useful insights in the study of CME-induced charge separation.     

模拟胃肠道消化液中小球藻类金属硫蛋白对镉离子的结合作用研究

利用锌诱导小球藻,通过提取分离和纯化,获得锌结合类金属硫蛋白(MT-like蛋白).通过透析过程,研究模拟胃、肠道消化液中MT-like蛋白对Cd2+的结合作用.结果表明,在模拟胃液中MT-like蛋白处于脱金属状态,与Cd2+的结合能力弱.而在肠消化液中,MT-like蛋白能与Cd2+结合,20 mg·L-1 MT-...     

罗丹明6G荧光猝灭法测定Hg2+离子

在PVA-124存在下,Hg2 与KI和罗丹明6G形成稳定的多元离子缔合物,并使罗丹明6G发生荧光猝灭,据此建立了测定Hg2 的荧光猝灭分析方法.方法的线性范围为4~60μg/L,检出限为2.5μg/L,用于水中Hg2 的测定,结果令人满意.     

Significant Enhancement of the Capacity and Cycling Stability of Lithium-Rich Manganese-Based Layered Cathode Materials via Molybdenum Surface Modification

Lithium-rich manganese-based layered cathode materials are considered to be one of the best options for next-generation lithium-ion batteries, owing to their ultra-high specific capacity (>250 mAh·g⁻¹) and platform voltage. However, their poor cycling stability, caused by the release of lattice oxygen as well as the electrode/electrolyte side reactions accompanying complex phase transformation, makes it difficult to use this material in practical applications. In this work, we suggest a molybdenum surface modification strategy to improve the electrochemical performance of Li_1.2Mn_0.54Ni_0.13Co_0.13O₂. The Mo-modified Li_1.2Mn_0.54Ni_0.13Co_0.13O₂ material exhibits an enhanced discharge specific capacity of up to 290.5 mAh·g⁻¹ (20 mA·g⁻¹) and a capacity retention rate of 82% (300 cycles at 200 mA·g⁻¹), compared with 261.2 mAh·g⁻¹ and a 70% retention rate for the material without Mo modification. The significantly enhanced performance of the modified material can be ascribed to the formation of a Mo-compound-involved nanolayer on the surface of the materials, which effectively lessens the electrolyte corrosion of the cathode, as well as the activation of Mo⁶⁺ towards Ni²⁺/Ni⁴⁺ redox couples and the pre-activation of a Mo compound. This study offers a facile and effective strategy to address the poor cyclability of lithium-rich manganese-based layered cathode materials.     

双硫腙包覆钛酸锶钡粉体对水中铅的吸附行为

用草酸化学共沉淀法合成了钛酸锶钡(BST)粉体, 以双硫腙为表面修饰剂, 采用静态浸渍法对钛酸锶钡粉体进行表面包覆修饰, 制备出新型固态粉体吸附剂. 利用X射线衍射(XRD)、扫描电镜(SEM)和傅立叶变换红外光谱(FTIR)进行了表征. 研究了该吸附剂对水中铅的吸附行为. 结果表明: 双硫腙通过与钛酸锶钡表面羟基形成氢键作用包覆于该粉体上; 当吸附介质pH值大于4时, 该吸附剂对水中的铅有较强的吸附能力; 室温下, 5 min内吸附达到平衡. 其吸附行为符合Langmuir吸附等温模型和HO准二级动力学方程式, 吸附焓变(ΔH)为19.42 kJ•mol^－1, 活化能(E_a)为22.187 kJ•mol^－1, 该吸附过程是吸热的物理过程. 吸附在双硫腙包覆钛酸锶钡粉体上的铅, 可用1 mol•L^－1的硝酸溶液进行洗脱. 建立了吸附富集、火焰原子吸收法测定水中铅的新方法, 应用于地表水和自来水中铅的测定, 取得了令人满意的结果.