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51.
52.
研究了根据酮麝香、1,3-二甲基-2,4-二硝基-5-叔丁基苯晶体生长速度的不同,从对二者均达到饱和的溶液中分离得到1,3-二甲基-2,4-二硝基-5-叔丁基苯晶体的过程,计算了晶体生长速度并进行了实验验证。 相似文献
53.
以四氢呋喃为溶剂 ,合成了含Sn、Fe的环戊烯基二羰基铁的异核双金属化合物 ,并对配合物进行了元素分析、IR光谱分析 ,使用SimensP4单晶衍射仪测定了配合物的晶体结构。结构分析表明 ,该配合物属于三斜晶系 ,空间群P - 1。晶胞参数 :a =10 0 79(2 )A° ,b =10 975 0 (10 )A°,c =17 14 5 (3)A° ;a =82 0 30 (10 )° ,β =77 770 (10 )°,γ =6 3 70 0 (10 )° ,Z =2 相似文献
54.
The crystal size distribution (CSD) measured by laser diffraction technique is obtained by assuming spherical crystals. If crystals are non-spheres, calibration is responsible for the true crystal size, particle number concentration and population density. In this paper, CSD calibration equations have been deduced. It was shown that when shape factors are size-independent, the weight percent of particles is not affected by crystal shape and calibration is just a horizontal shift of measured CSD. Calibration was taken for plate-like crystals of cefazolin sodium and rod-like crystals of l-threonine. The effect of CSD calibration on crystal growth kinetics has been investigated in l-threonine-water evaporation crystallization system. 相似文献
55.
Zhen-He Xu Yang-Guang Li En-Bo Wang Chao Qin Xin-Long Wang 《Inorganic chemistry communications》2006,9(12):1315-1318
Two new polyoxomolybdates Na5(NH4)16[Mo57Mn6(NO)6O174 (OH)3(H2O)24] · 44H2O (1) and (NH4)21[Mo57Cu6(NO)6O168(OH)3(H2O)24] · 53H2O (2) were synthesized in aqueous solution and characterized by elemental analysis, IR, TG analysis and single-crystal X-ray diffraction. They represent interesting examples of integrating and embedding magnetic 3d metal ions into the diamagnetic polyoxomolybdate host structure. 相似文献
56.
液晶聚酯由于具有特异的液晶行为和高强高模性能而越来越受到人们的关注。本文对液晶聚酯的液晶态形成原因、液晶态类型与链结构的关系、液晶态热稳定性及其成型加工性能进行了讨论,指出了提高液晶态热稳定性的方法及液晶聚酯的发展趋势。 相似文献
57.
到目前为止TiO2是较为成熟的半导体光催化材料,但因TiO2分散性差、量子利用率低、比表面积小、难回收等问题难以工业化。多孔金属有机框架MOFs的引入可增强TiO2/MOFs复合材料的光吸收性能,提高电子-空穴对分离和提高回收率。基于TiO2/MOFs制备时前驱体添加顺序不同,综述了TiO2/MOFs的三种制备方法(即Ship-in-a-bottle法、Bottle-around-ship法、One-pot法)及TiO2/MOFs光催化机理与性能影响因素,并探讨不同MOFs与TiO2结合的作用机理。最后,对TiO2/MOFs存在的问题提出建议。 相似文献
58.
The dynamics of the crystal size distribution in a continuous mixed suspension, mixed product removal crystallizer is modeled stochastically. The model is fairly general in that it involves a size-dependent growth rate function: this size-dependent growth rate as a possible cause of deviation on the behavior of the crystallizer from that of an idealized or simplified counterpart has been investigated based upon the model. 相似文献
59.
The role of Al in C-S-H: NMR, XRD, and compositional results for precipitated samples 总被引:2,自引:0,他引:2
X-ray diffraction, compositional analysis, and 29Si and 27Al MAS NMR spectroscopy of Al-substituted tobermorite-type C-S-H made by precipitation from solution provide significant new insight into the structural mechanisms of Al-substitution in this important and complicated phase. Al occurs in 4-, 5-, and 6-coordination (Al[4], Al[5], and Al[6]) and plays multiple structural roles. Al[4] occurs on the bridging tetrahedra of the drierkette Al-silicate chains, and Al[5] and Al[6] occur in the interlayer and perhaps on particle surfaces. Al does not enter either the central Ca-O sheet or the pairing tetrahedra of the tobermorite-type layers. Al[4] occurs on three types of bridging sites, Q3 sites that bridge across the interlayer; Q2 sites that are charge balanced by interlayer Ca+2, Na+, or H+; and Q2 sites that are most likely charge balanced by interlayer or surface Al[5] and Al[6] through Al[4]-O-Al[5,6] linkages. Although the data presented here are for relatively well-crystallized tobermorite-type C-S-H with C/S ratios ≤ 1.2, comparable spectral features for hydrated white cement pastes in previously published papers[30], [31] and [32] [M.D. Andersen, H.J. Jakobsen, J. Skibsted, Incorporation of aluminum in the calcium silicate hydrate (C-S-H) of hydrated Portland cements: a high-field 27Al and 29Si MAS NMR investigation Inorg. Chem. 42 (2003) 2280-2287; M.D. Andersen, H.J. Jakobsen, J. Skibsted, Characterization of white Portland cement hydration and the C-S-H structure in the presence of sodium aliminate by 27Al and 29Si MAS NMR spectroscopy, Cem. Concr. Res. 43 (2004) 857-868; M.D. Andersen, H. J. Jakobsen, J. Skibsted, A new aluminum-hydrate phase in hydrated Portland cements characterized by 27Al and 29Si MAS NMR spectroscopy, Cem. Concr. Res., submitted for publication.] indicate the presence of similar structural environments in the C-S-H of such pastes, and by implication OPC pastes. 相似文献
60.
Li-Na Zhu Lei Z. Zhang Wen-Zhen Wang Dai-Zheng Liao Peng Cheng Zong-Hui Jiang Shi-Ping Yan 《Inorganic chemistry communications》2002,5(12):434
A novel coordination polymer [Zn(BDC)(H2O)2]n 1 (where BDC = 1,4-benzenedicarboxylate), has been synthesized and characterized by X-ray diffraction. 1 crystallizes in the monoclinic space group C2/c, a=15.09(2) Å, b=5.058(7) Å, c=12.196(16) Å, β=103.62(2)°,
, Z=4. The most striking feature of 1 is that it consists of a high-dimensional network structure constructed from BDC-bridged 1-D chains via interchain hydrogen bonds. The coordination sphere of the zinc(II) ion is a distorted tetrahedron completed by four oxygen atoms from two water molecules and two BDC ligands. BDC adopts the bis-monodentated (syn–anti) coordination mode linking two adjacent zinc(II) ions. 1 shows strong blue photoluminescence as the result of the fluorescence from the intraligand emission excited state. 相似文献