接枝共聚法制备聚乙二醇(PEG)/聚乙烯醇(PVA)高分子固-固相变材料性能研究

用接枝共聚法将具有相变特征的聚乙二醇(PEG)接枝到具有较高熔点的聚乙烯醇(PVA)主链上,得到了系列性能稳定的PEG/PVA高分子固-固相转变材料,用DSC,WAXD和POM对其相变行为及形态结构进行了研究.结果表明,该材料呈现出可逆的固-固相转变特性;其结晶峰值温度和相变焓比纯PEG低,接枝率对相变温度和归一化相变焓影响不大;接枝率只影响结晶与熔融行为,不影响结晶结构.     

气相色谱-电子捕获检测法测定海水中十氯酮残留

通过考察提取溶剂、毛细管柱、净化条件及共溶出干扰物等因素对十氯酮测定的影响,建立了二氯甲烷液-液富集萃取、硫酸净化分离、气相色谱法(GC)-电子捕获检测器(ECD)测定海水介质中有机氯农药类持久性有机污染物十氯酮残留分析方法。1 L海水经50 mL二氯甲烷萃取富集,浓缩后采用硫酸净化,以1%(体积分数)甲醇/正己烷混合溶液转移定容后,采用DB-5非极性毛细管柱进行GC分离,电子捕获检测器可测定其中十氯酮的含量;该方法采用外标法定量,在5～100 μg/L范围内呈线性,线性相关系数为0.9989。低、中、高3个浓度水平的平均加标回收率为81%～108%,相对标准偏差为1.2%～5.1%(n=6)。方法的检出限为0.6 ng/L。结果表明,该方法灵敏度高,线性关系好,可以满足简便、快速、准确测定海水中十氯酮的要求。     

Cu-Zn-Zr/SBA-15介孔催化剂的制备及CO2加氢合成甲醇的催化性能

以具有骨架结构的SBA-15介孔分子筛为载体,采用浸渍法合成了具有高比表面积、不同金属氧化物含量的Cu-Zn-Zr介孔催化剂CZZx/SBA-15(x=0.3,0.4,0.5,0.6).采用N2吸附-脱附(BET)、X射线衍射(XRD)、H2程序升温还原(H2-TPR)、CO2吸附(CO2-TPD)和透射电子显微镜(TEM)等手段对样品进行了表征.在固定床反应器上评价了其CO2加氢合成甲醇的催化性能.实验结果表明,CZZx/SBA-15催化剂具有介孔结构,负载的Cu O,Zn O和Zr O2能够很好地分散在表面,并且负载氧化物晶粒尺寸不同.催化剂的铜比表面积SCu与甲醇催化活性呈近似线性关系,其中CZZ0.4/SBA-15催化剂表现出最大甲醇选择性(54.32%),与CZZ相比,甲醇选择性增加24.85%.随着金属氧化物负载量的增大,催化剂比表面积和SCu明显减小,甲醇选择性与收率也相应减小,负载型CZZx/SBA-15催化剂表面结构对CO2加氢合成甲醇反应活性起关键作用.     

电感耦合等离子体原子发射光谱(ICP-AES)法测定含硅镁合金中营养元素锶和钙

采用氢氟酸溶解硅,高氯酸冒烟除氢氟酸处理,利用电感耦合等离子体原子发射光谱(ICPAES)法测定生物医用可吸收含硅镁合金中营养元素锶和钙。对仪器参数以及被测元素的谱线选择进行了讨论。在选定最佳条件下,探讨了检测方法中检出限、精密度及加标回收率等指标,方法相对标准偏差小于1%(n=5),加标回收率为100.6%~117.2%。方法实用性强,已成功应用于含硅镁合金中锶和钙的测定。     

Ca3(PO4)2:Dy3+纳米荧光粉 的制备及发光性能研究

采用水热法制备出Ca3(PO4)2:Dy3+纳米荧光粉,通过XRD、SEM和荧光光谱对样品进行了分析,主要研究了制备工艺以及Dy3+离子掺杂浓度对材料发光性能的影响规律.研究结果表明:初始溶液pH值为7,反应釜填充度为80;,在180℃条件下反应24 h所得的Ca3(PO4)2:0.02 Dy3+纳米荧光粉发光性能最佳.SEM分析表明荧光粉颗粒的平均粒径为100 nm,分散性好.     

Studies on Liquid Crystalline Bis[4-(p-phenoxy)-phenylbenzoate]-Alkyldicarboxylate

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傅里叶变换红外光谱和近红外傅里叶变换拉曼光谱法无损鉴定中国字画

利用傅里叶变换红外(FTIR)和近红外傅里叶变换拉曼(NIR FT-Raman)光谱法鉴定了中国字画,结果表明：与荧光光谱法相比,根据谱峰的强度和位置可更容易地将真伪字画区别开来。拉曼光谱和红外光谱相互印证,互相补充,在鉴定中具有快速、准确、操作简单、重复性好、不需对样品进行预处理的优点,适于珍贵字画的无损鉴定。     

Review of the results of measurements of the fluxes of the charged components of galactic cosmic rays in the experiments PAMELA and AMS-02

The paper provides a review of the results of precision measurements of the fluxes of different charged components of galactic cosmic rays (positrons and antiprotons, protons and helium nuclei) in modern experiments with magnetic spectrometers PAMELA and AMS-02, operating successfully for a few years (since 2006 and 2011, respectively) in Earth orbit. A priority of the PAMELA spectrometer scientific discoveries is noted. It is also noted that the measurements from the AMS-02 experiment are of high statistical accuracy and have reliably confirmed previous data, having been able to advance to a higher energy range.     

Hybrid hetarylhydrazones and enamines of Furan-2(3H)-ones as a framework for the synthesis of poly-N-heterocycles

Substituted furan-2(3H)-ones can act as platform compounds to obtain easily various functionalized derivatives as well as heterocycles with different heteroatoms patterns. In this study, we suppose a simple and effective way to reach poly-N-heterocycles using a set of hybrid hetarylhydrazones and enamines based on furan-2(3H)-ones as a starting material. The presence of a few reaction centers in these the hybrid furan-2(3H)-one derivatives allows them to undergo some intramolecular rearrengements with opening furan ring as well as with keeping it unaffected followed by the increase of complexity of the resulting heterocycles, depending on reaction conditions. It was found that the reaction conditions and the nature of the substituents in the hydrazone fragment affect the direction of the interaction and the nature of the resulting products. Different approaches form a framework which allowed us to create a library of substituted annelated poly-N-heterocycles with highly prominent biological effects. Analysis of the possible biological effects was performed in silico which allows us to reveal leading structures among all synthesized compounds.     

Development of hydrogen–air fuel cells with membranes based on sulfonated polyheteroarylenes

Proton-conducting membranes based on sulfonated polynaphthoyleneimide (PNI) and polytriazole (PTA) are synthesized that can be used in portable hydrogen–air fuel cells (HAFC). Membrane–electrode assemblies (MEAs) based on sulfonated PNI and PTA membranes in individual HAFC manifested power and voltammetric characteristics exceeding the characteristics of MEA based on the commercial Nafion-212 membrane. Thus, the current density of 320 mA cm^–2 and the power density of 160 mW cm^–2 are obtained at the room temperature with no pressure or gas humidification at the voltage of 0.5 V. Also activity of the oxygen electroreduction Pt–Fe/C (30 wt % of metals in total) catalyst synthesized on the basis of coordination compounds is tested in MEA HAFC. It is shown that the values of power for MEAs with the cathodic Pt–Fe/C catalyst at the voltage of 0.5 V, at the room temperature, without additional pressure and gas humidification considerably exceed the corresponding values for MEAs with the commercial E-TEK 20% Pt/C catalyst.