ISSN:0232-1300    

DOI:10.1002/crat.2170310320

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170310321

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170310322

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170310323

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe experimental results of a study of the effect of supersaturation and temperature on the growth morphology of ammonium oxalate monohydrate [(NH4)2C2O4H2O; AO] single crystals obtained from aqueous solutions at 30 and 40 °C and supersaturation up to 9% are presented. The observations are analysed in terms of theoretical morphology, growth models and attachment energy for growth units in steps of growing faces

ISSN:0232-1300    

DOI:10.1002/crat.2170310302

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractZeolite ZSM‐5 was synthesised using ethyl silicate ester 40 and sodium aluminate so as to get the gel mix with SiO4/Al2O3= 90 employing TBPCl and TPABr templates separately (for comparison) at temperatures 423 K, 448 K, and 473 K. Nucleation and crystallisation processes were kinetically analysed. Activation energies for nucelation and crystallisation and the geometric factors have been evaluated. Correlations were found between the kinetic characteristics and the habits of the crystals formed. The study of the composition and morphology of the intermediates, with the support of SEM pictures, reveal the different mechanisms operating in the templating action of TBPCl and TPABr molecule

ISSN:0232-1300    

DOI:10.1002/crat.2170310303

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe effects of some commercial polymeric additives on the nucleation (induction period), crystal growth, and morphology of hydroxyapatite precipitated from pure solutions of the lattice ions have been examined. The inhibitory capacities of these additives for hydroxyapatite scale formed from whole juice samples under conditions similar to those operating in sugar mills have also been determined. The results show that poly(aspartic acid) withMwof 5700 is the most effective scale inhibitor.

ISSN:0232-1300    

DOI:10.1002/crat.2170310304

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractBaCu(C2O42.6 H2O is triclinic, P1, witha= 6.5405(9),b= 9.202(3),c= 10.939(1) Å, α = 85.46(2), β = 79.22(1), γ = 80.45(2),V= 636.99(1) Å3,Z= 2, D0= 2.14, Dc= 2.465 g. cm−3,R= 0.074,wR= 0.0746 for 2219 significant reflections |F0|≧ 6.0σF0. The barium has eleven coordinations and the coordination polyhedra is a capped antiprism. Six water oxygen atoms are coordinated whereas the other five are coming from the oxalate group. In the unit cell the molecules form a polymeric network. One lattice water molecule belongs to the coordinating water. The barium oxygen distances vary from 2.75 Å

ISSN:0232-1300    

DOI:10.1002/crat.2170310305

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe crystal structure of an adduct of sarcosine with sulfuric acid, (C3NO2H8)2SO2−4, has been determined at low temperature (140 K). The crystals are triclinic, space group = P1with the unit cell dimensions,a= 7.623(1) Å,b= 11.538(2) Å,c= 14.214(2) Å, α = 71.46(2)°, β = 74.36(2)°, γ = 86.46(2)°. Based on 4924 reflections with intensities larger than 3σ(I), the structure was refined to a conventionalRfactor of 0.038 giving e.s.d.s. in bond lengths and angles of 0.003 Å and 0.2°, respectively. There are two formula units in the asymmetric unit and both sulfate ions exist in two disordered orientations. The sulfate group 1 occupies the two orientations in the proportion 0.82/0.18 and sulfate group 2 in proportion 0.69/0.31. Both Orientations of the sulfate groups satisfy the hydrogen bonding scheme equally well.There is also a pseudo‐symmetry element within the asymmetric unit as one half of this unit is transformcd into the other by a translation of approximately one half along theb‐ andc‐axes. Thus, sarcosine molecule 1 is translated to sarcosine IV and sarcosine II to III. In the same manner, the sulfate group I in its main orientation is translated to the sulfate group 2 in its alternative orienta

ISSN:0232-1300    

DOI:10.1002/crat.2170310306

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractOptical absorption has been measured from 700 to 1300 nm for garnet single crystals by substituting Dy or Ga for Gd or Al of Dy3Ga5O12grown by the Czochralski method, and a suppression of unstable spiral‐shape growth on Dy3Ga5O12by the substitution was discussed relating the absorption spectra. The total absorption in the single crystals at the wavelength corresponding to the radiation from Ir crucible was decreased relatively with the increase of Gd or Al content. The decrease of this absorption in the single crystals is one of the causes to suppress the unstable spiral‐shape gro

ISSN:0232-1300    

DOI:10.1002/crat.2170310307

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY