水玻璃固化模拟月壤抗压强度增长机理分析

月球基地建设需要大量建筑材料,其中原位利用月壤能有效减少材料和运输成本。为了研究水玻璃固化模拟月壤抗压强度增长机理,分别进行了不同水玻璃掺量下的模拟月壤单轴抗压强度试验,X射线衍射和SEM(scanning electron microscope)电镜扫描试验,得到了水玻璃固化模拟月壤的单轴抗压强度变化规律,分析了能量变化特征和微观结构。研究结果表明：掺入适量水玻璃能提高模拟月壤的单轴抗压强度;采用掺量为5%的水玻璃,在85℃条件下养护28 d模拟月壤的抗压强度可达到3.23 MPa;此时模拟月壤的总能量和弹性能均达到最大值,随着水玻璃掺量不断增加,耗散能整体上呈现下降趋势。微观结构分析表明：水玻璃的碱激发作用和吸附作用所生成N—A—S—H凝胶、钙矾石(AFt)等水化产物填充在颗粒周围,松散的骨架颗粒通过凝胶胶结成致密的网状结构,从而使模拟月壤的强度得到提高。     

动力学控制合成原子精确的银纳米团簇及催化还原4-硝基苯酚

Synthesizing atomically precise Ag nanoclusters (NCs), which is essential for the general development of NCs, is quite challenging. In this study, we report the synthesis of high-purity atomically precise Ag NCs via a kinetically controlled strategy. The Ag NCs were prepared using a mild reducing agent via a one-pot method. The as-prepared Ag NCs were confirmed to be Ag₄₉(D-pen)₂₄ (D-pen: D-penicillamine) on the basis of their matrix-assisted laser desorption ionization time-of-flight mass spectrometric and thermogravimetric characteristics. The interfacial structures of the Ag NCs were illustrated by proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy. The Ag NCs were supported on activated carbon (AC) to form Ag NCs/AC, which displayed excellent activity for the catalytic reduction of 4-nitrophenol with a kinetic reaction rate constant k of 0.21 min?1. Such a high k value indicates that the composite could outperform several previously reported catalysts. Moreover, the catalytic activity of Ag NCs/AC remained nearly constant after six times of recycle, which suggests its excellent stability.     

系列芳香烃在土壤中洗脱规律的分子动力学模拟

以十六烷基间二甲苯磺酸钠为表面活性剂, 分别以苯、 萘、 菲、 芘为芳香烃相, 采用全原子分子动力学模拟方法, 研究芳香烃相改变对芳香烃/水界面性质的影响, 并分析界面厚度、 界面生成能、 界面张力、 表面活性剂分子与芳香烃分子间的径向分布函数和配位数以及芳香烃相与水相的扩散系数. 结果表明: 当芳香烃相为菲时, 界面厚度、 界面生成能和配位数最大; 界面张力及芳香烃相与水相的扩散系数最小, 具有较好的增溶和相容性, 但洗脱速率最慢.     

ICP-MS法测定食品添加剂氢氧化钠中五种重金属

目的:建立对基础干扰大的食品添加剂氢氧化钠中重金属的快速测定方法。方法:利用ICP-MS同时测定了食品添加剂氢氧化钠中砷、铅、镉、汞、铬五种重金属元素。结果:该方法完全克服了本体干扰大的缺点,五种元素标准曲线呈现良好的线性相关性,线性相关系数落在0.999 0~0.999 9的范围内;五种元素样品重复测定相对标准偏差(RSD)均小于3.7%,检出限在0.03~0.09 ug/L之间,加标回收率在91%~102%之间。结论:实现了对食品添加剂氢氧化钠中五种微量重金属元素准确快速分析。     

壳聚糖基复合海绵的制备及性能研究

以壳聚糖(CS)和海藻酸钠(SA)为材料,研究了两者不同质量比合成复合海绵(CS/SA)的效果,在此基础上,再加入羧甲基纤维素钠(CMC)进行改性,制备了改性复合海绵(CS/SA/CMC),用FTIR和SEM对其结构进行表征、形貌观察及吸水率分析.结果表明,在复合反应温度为25℃、冷冻干燥时间为24 h、氯化钙浓度为0.5%、壳聚糖与海藻酸钠按质量比为1∶3,复合海绵的孔径最大,吸水率高达900%以上,改性后吸水率提高了约400%.     

一种天然绿色素改性产物的光热稳定性研究

研究了藜蒿叶绿色素改性制取的绿色素铜钠盐的吸收光谱,测定了藜蒿叶绿色素铜钠盐在不同酸碱、不同环境下的光照、加热等条件下的稳定性。结果表明:藜蒿叶绿色素铜钠盐的吸收光谱与市售的叶绿素铜钠盐的特征吸收类似;藜蒿叶绿色素铜钠盐对酸碱、光照、热均有很好的耐受性。     

NaClO/IPA体系制备单晶硅太阳能电池绒面的研究

采用NaClO和IPA体系对单晶硅各向异性腐蚀制备绒面.通过紫外可见光光度计和扫描电镜对硅绒面的反射率、形貌进行了表征.结果表明,当NaClO为10%(质量分数,下同),IPA为5%,腐蚀温度为80℃,腐蚀时间为15 min时,能够得到均匀单晶硅绒面,硅片平均反射率达15%左右;与传统的Na OH/IPA腐蚀体系相比,该工艺制得的单晶硅绒面结构反射率低,有利于太阳能电池性能的提高.     

Electrochemically enhanced adsorption of PFOA and PFOS on multiwalled carbon nanotubes in continuous flow mode

It is important to develop efficient technologies on removal of perfluorooctanoic acid （PFOA） and perfluorooctane sulfonate （PFOS） from water due to their wide distribution and potential threat to human health. In this work, a durable and convenient electrosorption device was designed in continuous flow mode to investigate the adsorption of PFOX （X = A and S） on multiwalled carbon nanotubes （MWNTs） from water under electrochemical assistance. The electrosorption experiments were conducted under different influent and electrolyte concentrations, hydraulic retention time （HRT） and electrode distance to optimize the operation. The results showed that the highest removal efficiencies toward both PFOA and PFOS could come up to 90 % at 1 V. Compared with open circuit （OC） adsorption under the same conditions, the removal efficiencies were improved by 4.9 times （PFOA） and 4.2 times （PFOS） respectively. In addition, the MWNTs electrode was found to be reusable. These findings provide an efficient method to remove PFOX from water by electrosorption in continuous flow mode.     

Fe（CO）5光催化烯丙基苯异构化反应机理的理论研究

用ＣＮＤＯＳ／２方法研究并确认了羰基铁光催化烯丙基苯异构化反应的途径。证实了１，３－Ｈ转移机理，而ＨＦｅ（ＣＯ３）（π－烯丙基）机理是不合理的。计算所得活化能与实验值符合得很好。     

含砷、锑、锡硫化碱溶液中Na_2CO_3测定

关于含砷、锑、锡硫化碱溶液中Ｎａ２ＣＯ３测定方法的研究报导甚少。本文叙述了气体容量法用于含砷、锑、锡硫化碱溶液中Ｎａ２ＣＯ３的测定装置及手续。Ｎａ２Ｓ、Ｎａ２ＳＯ３、Ｎａ２Ｓ２Ｏ４、Ｎａ２Ｓｘ及其他钠盐、ＡｓⅢ、Ⅴ、ＳｂⅢ、Ⅴ、ＳｎⅣ、Ⅱ的存在不干扰。方法简便快速，测定一个试样仅需６～７分钟。方法准确度、重现性满意。对于２０～１００毫克Ｎａ２ＣＯ３的测定，结果相对误差小于３％。