天然产物法卡林二醇与人类GABAA受体相互作用的机制

通过分子动力学模拟、伞形采样模拟、结合自由能计算和分子对接等方法,研究了法卡林二醇在γ-氨基丁酸A型(GABA_A)受体上结合作用的模式和对GABA_A受体动态属性的影响,确定了3个有效结合位点均对此受体产生拮抗作用,为后续研究聚乙炔醇类化合物对GABA_A受体作用及相应药物开发提供了理论依据.     

胡椒碱与牛血清白蛋白的作用及Cu2+、Fe3+影响的研究

采用荧光光谱及紫外光谱法研究了胡椒碱与牛血清白蛋白（bovine serum albumin,BSA）的相互作用。实验结果表明：胡椒碱与BSA形成基态复合物从而猝灭BSA的内源性荧光,猝灭原因主要为静态猝灭和非辐射能量转移作用。胡椒碱对BSA的猝灭速率常数Kq为7．31×10^12 L·mol^-1·s^-1（25℃）和7．20×10^12 L·mol^-1·s^-1（37℃）,胡椒碱与BSA的结合常数K为1．02×10^7 L·mol^-1（25℃）和1．11×10^7 L·mol^-1（37℃）,结合位点数n为1．45（25℃）和1．46（37℃）。根据Ftirster偶极-偶极非辐射能量转移理论问题得到结合距离r为3．28nm（25℃）和3．30nm（37℃）。通过热力学参数的计算,确定胡椒碱与牛血清白蛋白的相互作用是一个熵增加和吉布斯自由能降低的自发过程,主要作用力为疏水作用力。同步荧光光谱表明,胡椒碱与BSA的相互作用没有引起BSA构象的变化。讨论了共存金属离子Cu^2＋、Fe^3＋对胡椒碱与BSA相互作用的影响。     

双功能复合材料g-C3N4/CdS/Ni催化光解水产氢和5-羟甲基糠醛氧化性能

采用高温煅烧法、 原位生长法和光还原法分三步制备出双功能复合光催化剂g-C₃N₄/CdS/Ni. 材料中CdS的引入可以增强光生电子和空穴的分离效率, Ni可以进一步提高光致产氢速率. 在以三乙醇胺(TEOA)为电子给体的水溶液中对所制备的材料进行了催化产氢性能测试, 并对材料中CdS的含量进行了优化. 结果表明, 25% (质量分数)CdS负载量的复合材料催化产氢性能最佳, 其催化产氢速率为4134.5 μmol·g^-1·h^-1, 是 g-C₃N₄/Ni催化产氢速率的115倍. 且Ni是一种良好的质子催化剂. 在此基础上, 以5-羟甲基糠醛(HMF)替代TEOA作为体系的电子给体, 其可以被选择性地催化氧化为增值化学品2, 5-二甲酰基呋喃(DFF). 当体系中HMF的转化率为82.3%, DFF的选择性为69.4%时, DFF的产率(57.2%)达到最高, 体系中H₂的产量为 51.8 μmol/g. g-C₃N₄/CdS/Ni复合材料可以在同一体系中进行催化光致产氢和HMF的选择性氧化.     

Development of niobium-promoted cobalt catalysts on carbon nanotubes for Fischer-Tropsch synthesis

Cobalt-based catalysts were prepared by a wet impregnation method on carbon nanotubes (CNTs) support and promoted with niobium.Samples were characterized by nitrogen adsorption,TEM,XRD,TPR,TPO and H2-TPD.Addition of niobium increased the dispersion of cobalt but decreased the catalysts reducibility.Fischer-Tropsch synthesis (FTS) was carried out in a fixed-bed microreactor at 543 K,1 atm and H2/CO=2 for 5 h.Addition of niobium enhanced the C5+ hydrocarbons selectivity by 39% and reduced methane selectivity by 59%.These effects were more pronounced for 0.04%Nb/Co/CNTs catalyst,compared with those observed for other niobium compositions.     

静电干燥原理及应用

简述了国内外物料干燥的技术水平，提出了一个全新原理的新型干燥技术－静电干燥，介绍其技术原理、技术特点，并对应用开发作了展望。     

DFT Calculations of Vibrational Frequencies of Carbon–Nitrogen Clusters: Raman Spectra of Carbon Nitrides

We have performed the calculation of structures of clusters containing carbon and nitrogen atoms. We determine the bond lengths in each case. We also calculate the vibrational frequencies of all of the clusters. We compare the calculated values of the vibrational frequencies with those measured by the Raman spectra of amorphous carbon nitrides. Some of the calculated frequencies are in agreement with those measured. We identity that linear structures and hence “back bones” are present in the glassy state.     

CaMoO4∶Eu3+发光材料的制备和发光性质的研究

用共沉淀法与高温焙烧法制备了样品CaMoO4:Eu3+.TG-DTA谱图表明:800℃时,样品吸收的能量最大,即形成稳定的CaMoO4:Eu3+结构.用XRD谱图进一步分析表明:800℃时,样品CaMoO4:Eu3+已形成CaMoO4的白钨矿结构.由于2个Eu3+取代3个Ca2+,导致了晶体产生微小的晶体缺陷,从而形成具有p-n结的半导体.经过激发和发射谱图的测试发现:这种缺陷结构不但可以使Eu3+禁戒的4f电子发生跃迁,而且可以使MoO42-的能量高效地传递给Eu3+.尤其使与MoO42-的发射特征峰(488 nm)部分重叠的Eu3+(465 nm)的7F0→5D2电子跃迁得到了极大的加强,进而在λex=465 nm的发射谱图中,自激活荧光体MoO42-的发射强度被大大减弱甚至猝灭,而Eu3+的5D0→7F2(612 nm)跃迁的红光发光强度被大大增强,使该材料成为有潜在应用价值的发光材料.     

新型链状化合物Mn3（dap）2（AsS3）2的溶剂热合成与表征

用溶剂热方法合成了一种新型链状化合物Mn3(dap)2(AsS3)2(dap=1,2-丙二胺),通过单晶X-射线衍射技术对其进行了晶体结构分析,该化合物属于单斜晶系,空间群C2/c。晶胞参数a=2.0869(14)nm,b=0.8745(6)nm,c=1.2496(8)nm,β=121.141(10)°,Z=4。标题化合物由两个相对称的[AsS3]3-三角锥与两个对称的过渡金属胺螯合物[Mn(dap)]2+通过共用S原子连接形成{[Mn(dap)]2(AsS3)2}2-原子簇,这些原子簇之间由四配位的Mn1进一步连接,形成沿c轴延伸的{Mn3(dap)2(AsS3)2}n一维链。紫外-可见漫反射光谱研究表明,化合物为宽带半导体,带隙Eg=2.5 eV。同时对该化合物进行了IR、XRD、XPS等表征。     

Direct measurement of the formation length of photons

We report the first observation of a shoulder in the radiation spectrum from GeV electrons in a structured target consisting of two thin and closely spaced foils. The position of the shoulder depends on the target spacing and is directly connected to the finite formation length of a low-energy photon emitted by an ultrarelativistic electron. With the present setup it is possible to control the separation of the foils on a μm scale and hence measure interference effects caused by the macroscopic dimensions of the formation length. Several theoretical groups have predicted this effect using different methods. Our observations have a preference for the modified theory by Blankenbecler but disagree with the results of Baier and Katkov.     

Fe(Ⅲ)掺杂金属有机骨架ZIF-67的合成及对甲基绿吸附性能的研究

本文采用沉淀法成功合成了Fe(Ⅲ)掺杂的ZIF-67,采用XRD、BET、SEM、XPS、FT-IR对样品进行了表征,并考察了ZIF-67及Fe/ZIF-67对甲基绿的吸附效果.结果 表明,7％Fe/ZIF-67对甲基绿染料表现出优越的吸附性能,60 min内可以将100 mg·L-1甲基绿溶液完全去除,优于纯ZIF-...