Ca2+ ⇌ Pb2+ exchange reaction of calcium silicate hydrate: Ca5Si6O18H2 · 4H2O

Recently it has been demonstrated that synthetic calcium silicate hydrate Ca₅Si₆O₁₈H₂ · 4H₂O shows cation exchange properties. In this paper we give the mass balance and thermodynamic data of the Ca²⁺ Pb²⁺ exchange which occurs in 1.1 nm tobermorite when placed in dilute Pb²⁺ solutions. The solid and solution phases have been analysed. The free energy of the exchange reaction at room temperature has been calculated. The X-ray powder diffraction data of the exchanged product have been reported. The crystallinity of the exchanger remains intact after ion exchange.     

从氢原子质子化模型计算H2+的结构参数

对氢分子离子提出了氢原子质子化的结构模型，从微观时标和宏观时标分析了H2+中库仑吸引力和两核排斥力的动态平衡，认为氢原子畸变后的电子云在两核中点产生e/8的电荷重心时可以束缚住一个裸质子；据此推导出键长、键能及力常数的计算公式；使用原子单位分别获得Re=2 au，De=0.109 735 au，k=0.109 735 au，与实验测定值及Bishop最精确的计算值惊人地接近。     

H2O—N2,H2O—H2O混合气体中H2O分子谱线的压力展宽系数

本文用改进的Ｂｕｃｋｉｎｇｈａｍ势模型，用ＩＯＳ方法计算了Ｈ２Ｏ－Ｎ２－Ｈ２Ｏ－Ｈ２Ｏ混合气体中Ｈ２Ｏ分子谱线在常温下的压力展半宽度，我们的计算结果与现有的实验值符合得较好。说明我们所采用的方法和势模型是比较成功的。     

高温下H2O—N2,H2O—H2O混合气体中H2O分子谱线的半宽度

本文用ＩＯＳ方法和我们改进的Ｂｕｃｋｉｎｇｈａｍ势计算了Ｈ２Ｏ－Ｎ２，Ｈ２Ｏ－Ｈ２Ｏ混合气体中Ｈ２Ｏ分子谱线在高温下（６００Ｋ，９００Ｋ，１２００Ｋ，１５００Ｋ）的压力加宽半宽度。分析了谱线半宽度随温度变化的规律，同时也讨论了半宽度与加宽和补加宽分子大小的关系。     

H3BO3对燃烧法制备SrAl2O4:Eu2+、Dy3+、Pr3+发光性能的影响

以硝酸盐和尿素为基质,采用燃烧法在较低炉温(600～620℃)下制备了SrAl2O4:Eu2+、Dy3+、Pr3+长余辉发光粉体.研究了H3BO3的加入对粉体的相组成、晶体结构、发光性能与长余辉特性的影响.通过对材料的XRD、激发和发射光谱、余辉衰减以及微观形貌分析.结果表明,H3BO3作为一种助溶剂,当其掺杂摩尔百分...     

FAAS法测定大气降水中的k+、Na+、Ca2+和Mg2+

本文应用FAAS法直接测定大气降水中阳离子K+、Na+、Ca2+、Mg2+。通过对火焰状态的选择,以减少和抑制电离的干扰。方法简便、快速、准确。加标回收率在94.0%-105.2%之间,RSD<5.07%。     

改性沸石对电镀废水中Pb2+、Zn2+、Ni2+的吸附

将天然沸石进行处理制备出多孔质改性沸石颗粒。在静态条件下，研究了改性沸石颗粒对重金属离子Pb^2 ,Zn^2 ,Ni^2 的吸附效果及条件，含Pb^2 ,Zn^2 ,Ni^2 的电镀废水经改性沸石颗粒吸附后，废水中Pb^2 ,Zn^2 ,Ni^2 的含量低于国家排放标准。     

改性海泡石对电镀废水中Pb2+、Cu2+、Cd2+的吸附

用盐酸溶液对海泡石处理后在 4 5 0℃下灼烧 ,制备出改性海泡石。在动态条件下 ,研究了改性海泡石对重金属离子Pb2 +、Cu2 +、Cd2 +的吸附效果及条件。探讨了改性海泡石对重金属离子Pb2 +、Cu2 +、Cd2 +的吸附机理。含Pb2 +、Cu2 +、Cd2 +的电镀废水经改性海泡石吸附后 ,重金属离子含量显著低于国家排放标准     

Effect of Ni+2-substituted Fe2TiO5 on the H2-reduction and CO2 Catalytic Decomposition Reactions at 500℃

CO2 is a major component of the greenhouse gases, which causes the global warming. To reduce CO2 gas, high activity nanosized Ni＋2 substituted Fe2TiO5 samples were synthesized by conventional ceramic method. The effect of the composition of the synthesized ferrite on the H2-reduction and CO2-catalytic decomposition was investigated. Fe2TiO5 （iron titanate） phase that has a nanocrystallite size of -80 nm is formed as a result of heating Fe2O3 and TiO2 while the addition of NiO leads to the formation of new phases （-80 nm） NiTiO3 and NiFe2O4, but the mixed solid of NiO and Fe2O3 results in the formation of NiFe2O4 only. Samples with Ni^＋2=0 shows the lowest reduction extent （20%）; as the extent of Ni＋2 increases, the extent of reduction increases. The increase in the reduction percent is attributed to the presence of NiTiO3 and NiFe2O4 phases, which are more reducible phases than Fe2TiO5. The CO2 decomposition reactions were monitored by thermogravimetric analysis （TGA） experiments. The oxidation of the H2-reduced Ni＋2 substituted Fe2TiO5 at 500℃ was investigated. As Ni^＋2 increases, the rate of reoxidation increases. Samples with the highest reduction extents gave the highest reoxidation extent, which is attributed to the highly porous nature and deficiency in oxygen due to the presence of metallic Fe, Ni and/or FeNi alloy. X-ray diffraction （XRD） and transmission electron microscopy （TEM） of oxidized samples show also the presence of carbon in the sample containing Ni＋2〉0, which appears in the form of nanotubes （25 nm）.     

膨润土吸附去除Zn2+、Cd2+的研究

在静态条件下,利用天然及活化膨润土对重金属Zn^2 、Cd^2 的单组分水溶液进行吸附研究。结果表明,膨润土对重金属离子具有较强的吸附性能,PH值是影响吸附的主要因素,离子交换和表面络合反应是主要吸附形式,基本符合Langmuir吸附等温线。     

添加剂对储能材料CaCl2·6H2O+Ca(NO3)2·4H2O 相变温度和过冷温度的影响及其熔盐结构

本文研究了储能材料CaCl_2·6H_2O-Ca(NO_3)_2·4H_2O的储能性能,并对影响其储能性能的结晶过冷问题和盐水分离问题进行了详细研究。发现单组分成核剂SrCl_2·6H_2O、BaCO_3、BaCl_2对该体系的过冷问题改性效果较好,能使熔盐的过冷度降低到2.3℃左右;增稠剂羧甲基四乙酸钠(CMC)对盐水分离问题有一定的改善,但会增大熔盐的过冷度。混合成核剂SrCl_2·6H_2O(2%)+BaCl_2(1%)+CMC (0.5%)对熔盐过冷问题改性较好,可使过冷度降低到1.8℃左右。储能材料改性前后相变焓变化不大,均在140J/g左右。在此基础上研究了熔盐CaCl_2·6H_2O和Ca(NO_3)_2·4H_2O的微观存在形式,从微观结构方面对熔盐存在的过冷和盐水分离问题进行了初步讨论。     

镀锌板上Ca2+、Zn2+、Mn2+三元磷化工艺的研究

研究了电镀锌板上一种新型ca2 、Zn2 、Mn2 三元磷化工艺.通过扫描电镜(SEM)、光电子能谱(XPS)、电化学交流阻抗等方法研究了Ca2 浓度对磷化膜晶粒形态、膜层结构及膜层耐腐蚀性能的影响.采用时间电位曲线和扫描电镜(SEM)分析研究了这种新型三元磷化膜在镀锌板上的生长机理且与传统zn2 、Mn2 、Ni2 三元磷化膜微观形态及耐蚀性能进行了比较.结果表明,在最佳Ca2 浓度下,电镀锌板上三元磷化膜具有类似钢铁表面粒状磷化膜的微观形态,比传统三元磷化膜晶粒结构更细致、耐蚀性更好.     

壳聚糖H2O2法降解研究

着重讨论了壳聚糖的主要降解方法及使用氧化降解法制备低聚壳聚糖的情况.采用正交设计,探讨降解条件对产物脱乙酰度、特性粘度等的影响.     

碳钢/H2SO4+K2Cr2O7/Pt体系自腐蚀过程的电位振荡现象

研究了碳钢/H2SO4 K2Cr2O7/Pt体系中的电位振荡现象,如周期振荡、准周期振荡和混沌振荡等,并对其振荡机理进行了初步分析和讨论,可以发现,在同样的电解质溶液中,它同纯铁的动力学行为类似且具有比纯铁更为复杂的动力学行为,电解质溶液的成分和浓度对电位振荡的产生起关键作用,电极的表面性质也对电位振荡现象产生重要的影响。     

Mg2+、Cu2+对铝无烟化学抛光的协同效应

根据金属化学抛光的黏液膜或凹凸理论,在磷酸-硫酸基础液中加入组合添加剂,对工业纯铝进行无烟化学抛光,以改善抛光效果,并与传统三酸抛光效果进行对比.传统的无烟抛光剂中采用的Cu、Ni等重金属添加剂有利于氧化膜的生成,并具有明显的整平效果.抛光试验结果表明,当添加等量的Mg2 后,能够和cu2 发生协同效应,有利于抛光过程的进行,改善抛光质量.其最佳加入量为:1.2～1.8 g/L Cu2 Cu2 、Mg2 最佳比例为1:1.     

高纯PH3和B2H6中微量H2、O2、N2的分析

前言 半导体工艺过程及大规模集成电路生产中所使用的高纯PH3和B2H6，由于其中含有O2、N2等杂质成份，直接影响了电子产品的质量，所以，必须严格地加以检测和控制。目前，一些发达国家对特气产品中杂质的监控十分重视，且都相应地研制出专门仪器进行检测。如法国TBT公司所研制的TBT色谱仪，对磷烷、硅烷、砷烷及乙硼烷中永久性气体杂质和总烃杂质都能进行检测。     

Mechanism of decomposition of UO2(NO3)2·6H2O + Fe(NO3)3·9H2O mixture under the action of microwave radiation

Products of decomposition of the UO₂(NO₃)₂·6H₂O + Fe(NO₃)₃·9H₂O mixture under the action of microwave radiation (MWR) were studied by thermal gravimetric, X-ray phase, and chemical analyses. The results obtained were compared to the published data for various U and Fe compounds. The final products of decomposition of the UO₂(NO₃)₂·6H₂O + Fe(NO₃)₃·9H₂O mixture under the action of MWR for 3?C5 min (the maximal temperature of the process, equal to 140?C150°, is attained within 2?C3 min of irradiation), apart from gaseous products, are UO₂(OH)NO₃, UO₃, and Fe₂O₃. The action of MWR on the UO₂(NO₃)₂·6H₂O + Fe(NO₃)₃·9H₂O mixture under the examined conditions does not lead to the formation of uranyl ferrite.     

X-ray powder diffraction and IR study of NaMg(H2O)2[BP2O8]·H2O and NH4Mg(H2O)2[BP2O8]·H2O

NaMg(H₂O)₂[BP₂O₈]·H₂O was prepared by hydrothermal synthesis and was characterized by X-ray powder difraction and IR method. The title compound was synthesized from MgCl₂·6H₂O, NaBO₃·4H₂O, and (NH₄)₂HPO₄ with variable molar ratios using hydrothermal method by heating at 165 °C for 3 days. The X-ray powder diffraction data was indexed in hexagonal system, the unit cell parameters were found to be as a = 9.428, c = 15.82 Å, Z = 4 and the space group is P6₁22. It is isostructural with M^lM^ll(H₂O)[BP₂O₈] type compounds where M^l = Na, K; M^ll = Mg, Mn, Fe, Co, Ni and Zn. In addition NH₄Mg(H₂O)₂[BP₂O₈]·H₂O was also synthesized the first time in this research. Its unit cell parameters and hkl values were in good agreement with the sodium magnesium compound. The unit cell parameters are a = 9.529, c = 15.736 Å. The indexed X-ray powder diffraction data of both compounds which were not reported in the literature is presented in this work. The IR data of NaMg(H₂O)₂[BP₂O₈]·H₂O is also reported.     

常压N2+H2O气液DBD等离子体处理PP无纺布的超亲水性研究北大核心CSCD

采用接触式气液介质阻挡放电装置,采用常压N2和N2+去离子水(H2O)两种介质阻挡放电等离子体对PP无纺布的表面进行改性研究,实验结果表明PP无纺布经N2+H2O等离子体处理60 s后表面出现了超亲水,其表面水接触角降为0°。但是经N2等离子体处理60 s,表面接触角由未处理时的115.8°降低至62°,并未出现超亲水。通过扫描电镜、X射线光电子能谱的对比分析发现,PP经N2+H2O等离子体处理60 s后,表面出现粘连、刻蚀,表面C1s的含量由原来的96.7%下降到31.8%,同时表面O1s和N1s的含量分别增加到38.4%和29.8%,比PP经N2等离子体处理60 s后C1s多降低20.8%,而O1s和N1s的含量分别多增加了12.7%和8.1%,并且PP表面分子出现明显的交联;而FTIR-ATR的结果进一步表明,PP经N2+H2O等离子体处理60 s后表面接入更多的-OH,从而导致表面超亲水。