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O. Šolcová L. Matějová P. Topka Z. Musilová P. Schneider 《Journal of Porous Materials》2011,18(5):557-565
Argon(87 K) and nitrogen(77 K) adsorption of three types of porous samples (microporous, microporous-mesoporous and mesoporous)
was evaluated. The shapes of isotherms, specific surface areas, mesopore-, micropore- and net pore volumes, pore-size distributions
(PSD) and positions of micropore and mesopore PSD’s maxima were compared to ascertain the credibility of individual adsorbates
for the texture information estimation. The shapes of adsorption isotherms for Ar and N2 of all samples are similar and the adsorbed amounts at relative pressure x = 0.975 differ slightly. For mesoporous samples some differences are observed between specific mesopore surface areas derived
from nitrogen and argon isotherms. Radii of pore size maxima from Ar(87 K) PSD’s are on average systematically lower than
from N2(77 K) for all samples. The Saito-Foley approach for ZSM-5 samples gives consistently lower mean pore radius from N2(77 K) adsorbate than from Ar(87 K). This difference probably arises from the multiplication factor, Ω, in the Saito-Foley
equation which includes physical properties (magnetic susceptibility, polarizability etc. at 77 and 87 K) and is not easy to obtain with sufficient precision. The use of both adsorbates Ar(87 K) and N2(77 K) possesses some advantages as well some disadvantages and the comparison of textural properties of individual samples
must be evaluated with respect to adsorbate. 相似文献
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叙述了Fe3 、Zn2 、Mn2 、Cu2 、Ca2 、Mg2 等离子共存体系中采用六次甲基四胺 -铜试剂沉淀除去Fe3 、Zn2 、Mn2 、Cu2 等干扰离子 ,用EDTA滴定钙镁的方法 ,该方法钙的回收率在 99.7%~ 10 0 .3 % ;镁的回收率在 10 0 .0 %~ 10 0 .4% ,标准偏差为 0 .0 2 2。 相似文献
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通过共沉淀法制备多组添加TiO_(2)助剂改性的Cu-ZnO-Al_(2)O_(3)(CZA)基甲醇合成催化剂(TiO_(2)掺杂CZA,即TiO_(2)/CZA,TiO_(2)/CZA=0/10,0.5/10,1.0/10,2.0/10和3.0/10),采用氮气吸脱附BET、H_(2)-TPR、NH_(3)-TPD和SEM等技术对其进行表征,并考察不同助剂添加量对合成气制甲醇催化性能的影响。结果表明,TiO_(2)助剂可以调变催化剂活性组分铜物种的分散度、比表面积、晶粒大小和形貌结构等。其中TiO_(2)/CZA比低于0.5/10时,催化剂具有粒度小、颗粒分布均匀的特点,能够促进Cu物种分散,使催化剂表面酸性降低,有利于催化剂表面对CO和H_(2)的吸附和活化,促进CO转化和甲醇的生成。当TiO_(2)/CZA比为0.5/10时,催化剂比表面积为102.20 m^(2)·g^(-1),CO转化率为64.2%,催化剂活性最好;而当TiO_(2)/CZA比高于0.5/10时,过量助剂可能占据催化剂孔道和覆盖表面活性位,降低活性组分分散性,造成CuO与H_(2)有效接触减少,催化活性下降。因此,添加适量TiO_(2)助剂可促进CO加氢反应合成甲醇,增强CZA催化剂的耐热稳定性。 相似文献
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《Inorganic chemistry communications》2002,5(12):1086-1089
A novel copper complex polymer {[Cu4(dmg)2(Hdmg)2(H2dmg)2(H2O)2](ClO4)2}∞ (H2dmg=dimethylglyoxime) has been synthesized and its structure was determined by X-ray single crystal diffraction methods. The complex polymer is like a 1D infinite chain with topological type as a sequence of fused rings connected by out-planar CuO bonds, in which oximato groups (NO−) act as two-dentate bridges to link center Cu2+ cations. This structure shows that oximes have great perspective in coordination chemistry and supramolecular polymer chemistry. Molecular structure and spectroscopic properties of the polymer complex were discussed in the article. 相似文献
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《聚氨酯工业》1997,(2)
喷涂型聚氨酯涂料及泡沫美国FuturaCoatings公司1996年推出了几种喷涂型PU体系。其中Ultra系列为喷涂型PU“结构性”弹性体,其模量从低到高都有。该类产品固化快,一般在10~15S内固化。在开口模具中喷射成型,脱模时间2~10min。该系列可用于零部件的制造和泡沫塑料表面保护性涂层,应用于造船工业、车辆部件、建筑部件等。Futurathane系列为单或双组分喷涂型屋顶施IPU涂料,可在喷涂PU泡沫塑料上形成一柔韧性防水层。Ultracore系列为喷涂型PU结构泡沫塑料,是不饱和树脂/聚氨酯共混材料,固化快、重量轻、韧性好。该公司称它可代… 相似文献
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《聚氨酯工业》1997,(4)
延长凝胶时间的RIM聚氨酯弹性体美国Bayer公司的BayflexXGT-140是一种可反应注射成型的聚氨酯弹性体体系,它具有稍长的凝胶时间以利于填满模腔。该材料已被美国Utili-master公司用于制造新型大卡车的挡泥板。重5.4kg的挡泥板注料时间约8s,在65C生产周期为4min,模塑品室温下弯曲模量965MPa。刘益军摘译自PlasticsTechnology,1997,43(1):47IVC公司开发了软质聚氨酯涂料消息动态英国IVC(Inco真空涂料)公司新开发的软性聚氨酯涂料系列具有羊皮般手感及美观,可用于与手接触的塑料制品的涂层。典型应用包括移动电话、电话… 相似文献
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《聚氨酯工业》1998,(3)
织物用PU热熔胶Bostic公司的Supergrip2000/9716是一种100%因含量聚氨酯热熔胶粘剂。它具有高弹性、良好的初粘性及耐水解性等优点,可用于高弹性织物和服装。这些织物有望用于病员眼、雨衣、护膝及其他保护用品。此热熔胶在环境湿气中固化。典型物性为:100C粘度25Pa.s,0.13mm厚的薄膜测得的拉伸强度为6.55MPa.伸长率350%.且在撤去外力后完全回复原形。刘益军摘译自AdhesivesAge,1997.40(10):10PU汽车仪表板在美国芝加哥的NPE’97上展示了两种全聚氨酯仪表板。一种是采用BASF公司新型聚聚氨酯原料ElastolitM制得的… 相似文献
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采用溶液法合成了分子式为[Cu2(phen)2(OH)2(H2O)2][Cu2(phen)2(OH)2Cl2]Cl2.6H2O的配合物。通过元素分析、红外光谱、紫外光谱和X-射线单晶衍射对配合物进行了表征;此外,还对该配合物进行了非等温热分解动力学研究。研究表明,配合物中有两组双核配位单元,分别为[Cu2(phen)2(OH)2(H2O)2]2+和[Cu2(phen)2(OH)2Cl2];两个配位单元的中心原子铜均为五配位的,具有扭曲的四方锥结构,配合物通过氢键作用形成超分子结构。此配合物的热分解反应是分两步进行的,第一步反应的动力学方程为dαdT=Aφ.exp-E()R T3/2[(1-α)43(1-α)-13-]1-1,活化能E=151.8kJ/mol,指前因子lgA=16.9435;第二步反应的动力学方程为dαdT=Aφ.exp-E()R T32[(1-α)43(1-α)-13-]1-1,活化能E=201.5kJ/mol,指前因子lgA=7.5447。 相似文献
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