基于Monte Carlo模拟的三种不同结构单电子动态存储器特性比较

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呋喃醛双缩二氨基硫脲腙的合成和结构测定

由ＣＳ＿２，Ｎ＿２Ｈ＿４和Ｃ＿４Ｈ＿３ＯＣＨＯ合成Ｃ＿（１１）Ｈ＿（１０）Ｎ＿４Ｏ＿２Ｓ·１／２ＤＭＦ，Ｍ＿ｒ＝２９８．７９，橙黄针状晶体，三斜晶系，空间群Ｐ１，ａ＝８．９１２（３），ｂ＝９．９８９（３），ｃ＝１６．１０７（４），ａ＝８３．６１８（６），β＝８７．１０５（５），γ＝８６．１１５（３）°，Ｖ＝１４２０．４，Ｚ＝４，Ｄ＿ｘ＝１．３９７ｇ／ｃｍ￣３，λ（ＭｏＫα）＝０．７１０７３，μ＝２．１７０ｃｍ￣（－１），Ｆ（０００）＝６１６。３２２６个可观察的独立反射（Ｉ＞３σ（Ｉ）使结构顺利解出，并精修到Ｒ＝０．０４８，△ρ＿（ｍａｘ）＝０．２８６。单晶体结构分析表明不对称单位含有二个非结晶学对称相关的独立分子和一个溶剂分子ＤＭＦ，通过ＤＭＦ中的ｏ原子和亚胺Ｈ形成Ｎ－Ｈ…Ｏ…Ｈ－Ｎ类型双氢键，使两个分立分子缔合一起而自成独立的结构单元。     

多孔Ni、Ni-Mo合金及其氧化物的制备与析氢性能

采用快速凝固结合脱合金化的方法制备了纳米多孔Ni、Ni-Mo合金及其氧化物电极材料,通过XRD、SEM、TEM、BET等对电极的物相、形貌结构、孔径分布进行表征,通过线性扫描伏安法、Tafel斜率和计时电位等方法测试多孔电极的电催化析氢性能。结果显示,制备的电极材料在10 mA·cm-2电流密度下Ni-Mo合金析氢活性最强,析氢过程由Volmer-Heyrovsky步骤控制,其表观交换电流密度为0.25 mA·cm-2,经10 000 s恒电流密度(100 mA·cm-2)电解后析氢过电位(η)仅增加39 mV,表现出优良的析氢稳定性。Ni-Mo合金电极比表面积的提高和本征催化活性的改善使其获得了更低的析氢过电位。     

一种新的具有双螺旋结构特征的光学活性分子方的设计、合成及其光学性质

分别从手性构型高度稳定的(R)和(S)-2,2'-二乙炔基-1,1'-联萘模板出发, 通过保护基的控制导入、偶联反应、保护基脱去以及分子间偶合成环4个步骤成功地合成了一种具有螺旋结构特征的新的光学活性分子方(Molecular square)(R,R,R,R)-1和(S,S,S,S)-1. 用MS, IR, UV-Vis, 1H和13C NMR以及元素分析等方法对目标化合物进行了结构表征. 测定并分析比较了2个目标化合物的比旋光度[α]D和圆二色性(CD)等光学性质. 在CH2Cl2溶液中, 异构体(R,R,R,R)-1和(S,S,S,S)-1的[α]25D值分别为+887.3°和-889.7°, 并且其CD谱表现出对称的镜像特征.     

Ⅱ型糖尿病大鼠神经视网膜组织中差异蛋白质分析

以高脂饮食联合小剂量链脲菌素(Streptozotocin, STZ ) 注射方法诱导大鼠II型糖尿病 (T2DM) 模型为研究对象, 采用比较蛋白质组学技术鉴定和分析早期糖尿病神经视网膜差异表达蛋白.通过联用液氮内研磨、冰浴超声、高速离心提取全蛋白技术,提取每只大鼠神经视网膜全蛋白质总量约900 μg.采用双向凝胶电泳(2-DE) 分离技术,获得2500个以上可辩认的蛋白质斑点.通过蛋白质组学比对技术筛选出糖尿病状态下神经视网膜差异表达蛋白,用基质辅助激光解吸电离飞行时间串联质谱 (MALDI-TOF- MS/MS) 和肽质量指纹图谱 (PMF) 鉴定出20个差异蛋白点.按照Gene Ontology (GO)分类体系,对差异蛋白归类分析,揭示其亚细胞定位和分子功能.应用Pathway Studio软件对差异表达蛋白的生物学意义进行分析,认为凋亡是早期糖尿病视网膜病变(Diabetic retinopathy,DR) 重要的细胞事件;AnnexinΙ、CRYAB、mtHsp70蛋白是与病理过程相关的关键蛋白,对研究DR致病机制有重要意义.     

Selective Tandem Inter/intramolecular Eglington Coupling for Chiral Cyclophyne Synthesis

Tandem inter- and intramolecular Eglington couplings take place with good selectivity to afford an enantiopure three-dimensional cyclophyne with a large cavity.     

Synthesis,Characterization and Coordination Properties of a Novel Thiacalix[4]arene with Diagonal Quinolin-8-yloxy Pendants

A novel conic thiacalix[4]arene derivative (1) with diagonal quinolin-8-yloxy pendants via oxyethylene spacer has been synthesized in one step. The coordination properties of the new ligand towards Ni^2 + , Co^2 +  and Zn^2 +  ions were studied by UV–vis, fluorescent spectra and ¹H NMR titration. The results showed that 1 formed very stable complexes with the three metal ions, and the stoichiometries of 1-Ni^2 + , 1-Co^2 +  and 1-Zn^2 +  were 1:1, 1:2 and 1:2, respectively.     

Chiral resolution and bioactivity of enantiomeric furofuran lignans from Juglans mandshurica Maxim

Abstract

Enantiomers have generally been reported mostly for racemic mixtures with a 1:1 ratio, as in that case there were weak Cotton effects in the ECD spectrum and negligible optical rotations. A furofuran lignan (sesamin), with a remarkable rotation and significant Cotton effects, was isolated from Juglans mandshurica Maxim. Subsequently, sesamin was resolved by chiral HPLC to afford a pair of enantiomers, (+)-sesamin (a) and (?)-sesamin (b), in a ratio of approximately 1:3. Their absolute configurations were determined by computational analysis of their electronic circular dichroism (ECD) spectrum. In addition, the pair of enantiomers were evaluated for the inhibition of self-induced Aβ aggregation. Interestingly, (+)-sesamin (a) (67.7%) and (?)-sesamin (b) (80.6%) exhibited different degrees of anti-Aβ aggregation activity. The different inhibition profiles were further explained by molecular dynamics and docking simulation study.     

Dynamical precession of spin in the two-dimensional spin-orbit coupled systems

We investigate the spin dynamics in the two-dimensional spin-orbit coupled system subject to an in-plane (x-y plane) constant electric field, which is assumed to be turned on at the moment $t=0$. The equation of spin precession in linear response to the switch-on of the electric field is derived in terms of Heisenberg's equation by the perturbation method up to the first order of the electric field. The dissipative effect, which is responsible for bringing the dynamical response to an asymptotic result, is phenomenologically implemented à la the Landau-Lifshitz-Gilbert equation by introducing damping terms upon the equation of spin dynamics. Mediated by the dissipative effect, the resulting spin dynamics asymptotes to a stationary state, where the spin and the momentum-dependent effective magnetic field are aligned again and have nonzero components in the out-of-plane (z) direction. In the linear response regime, the asymptotic response obtained by the dynamical treatment is in full agreement with the stationary response as calculated in the Kubo formula, which is a time-independent approach treating the applied electric field as completely time-independent. Our method provides a new perspective on the connection between the dynamical and stationary responses.     

The Coulomb effect on a low-energy structure in above-threshold ionization spectra induced by mid-infrared laser pulses

We investigate the low-energy structure(LES)in the above-threshold ionization spectrum at a mid-infrared laser wavelength with a semiclassical model.Using a softened Coulomb potential(CP)and changing the softening parameter,we show that though the very low-energy structure(VLES)and high low-energy structure(HLES)are both due to the interaction between the ionic CP and the electron,the two structures have different physical mechanisms:the VLES can be attributed to the electron–ion Coulomb interaction at a rather small distance and the HLES is more likely to be ascribed to the electron–ion Coulomb interaction at a large distance.