مجله بلور شناسی و کانی شناسی ایران
سال سوم شماره 1 (پیاپی 7، بهار 1374)

Five layers of GaAs:Te(n=2x 1018 cmchr('39') Alo.4GaQ.6As:Sn(n=5xWI6 em,3}. GaAs, Alo .• GaQ.6As: Ge(p=3xW17 em-3),GaM: GC(p= IXlO18cm 3) were grown by supercooled LiquidPhase Epilaxy on n-GaAs(IOO) substrate. The cooling rate of thefurnace was SCI up With U. I"C/min al T=860°C. The firSI layerwas grown at T=840°C and Ihe la sl one at T=827°C. Thethi ckness were varied between 0.1 10 8,um by controlling thesupercooling IcmperalUre and growth time. Quality and quantilYof epitaxial layers were examined by TEM, SEM, PIXE and x-ray,

Modern X-ray systems used in research are equippedwith computers. To modernize the ava ilable systems which arenot attached to such computers and in order to have a rapidaccess to the data extracted from the system. furnishing suchsystems seems necessary. In this paper a research conducted atthe university ofTabriz to arrive at the above mentioned aimsand to have an access to tbe results obtained from the X-raysystems, the process of computer analysis of XRF and XRDdata are presented.

[Cd(NO)z(u rea)4J was synthesized by reaction ofcadmium nitrate and urea under certain conditions. Thedimensions of used crystal were O.47xO.40x0.58 mm. Themolecular structure has been determined by SHELX-86program. This complex crystalizes in monoclinic space groupP2}/a with two molecules per uni. cell. Lattice parameters of thiscompound are:a~7.6060 A b~12.7740 A c~9.0370 A P~llchr('39').07"After last least - square cycle, the final Rand Rw values are0.0556 and 0.0685 , respectivley. According to IR and molecularstructure studies, urea molecule is coordinated through oxygen.

The piezoelectric crystals conven mechanical energyinlo clcclrical energy and vice versa. This propeny has manyapplications in science and technology. In this paper we reporlthe growth of KDP single crystal OUI of a super-saturated KDPliquid by controling the temperature and the pH. We studied theeffect of the variation of the pH and temperature on the KDPsingle crystal. We found that the best pH range is 4.5 In 5.2, andalso that the mOSl appropriate temperature range is 25°C to30"C.

produced iron - ferrtie(Fc304) by methods of dryreduction of hematite(a-Fez03) are investigated on magneticphases and properties with X-ray diffraclomclcry and alsomeasurements of magnelisalion. The resulls show that thepercentage and kind of reductive materials, the heatingtemperalUre and time have serious effects in production ofFe,O,.

Hyd rot hermal synthes is of faujasite type zeolite in ashort crysta llizat ion period could be performed by preparing afresh aqueous nucleation solution mixed with an aluminosilicalcgel into a teflon tube placed in thc stainless-steel microautoclave.Effects of source of s ilica, sodium silicate, and colloidal silica andalso aging of nucleation solution were examined 10 prepare ahig hly crys talline and pure fauja s ite. in all experimentscomposition of the final gel was 3Na20,1 AI20 1,lOSi02, 160H20.Mcthods of X-ray Diffraction, Scanning Electron Microscopy.Energy Dispe rsive X-ray spectrometry associated with SEM,infrared spectroscopy and Thermogravimetric Analysis were uesdto study the crys tallinity and re lat ed properties. UV-VISspectrosco py were used to study the nucleation so lution .Ultra-fine and pure clys tals of fauja s ite were obtained from anucleation so lution prepared from AI, NaOH and colloidal silica.Average crystal size was l,um and calculated unil celJ formulawas Na491(AIOZ)49(Si02)l41j.255H20 Solid phase mate rialsprecipitated from the aqueous nucleation solution arter sevendays, exami ned by X-ray difrreact ion showed btoaded peaks offaujasite. This supports the hypot hesis that crystallization mayoriginated form liquid phase.

Single crys tals have been grown rrom ancient Egypt.Crys tal growth Slall ... u ... I •• ~ • • . 1 " - •• v •• ,1940 until now. Four melt.odS have been used to prepare singlecrys tal s: gr~-rr-onrsOlu tiOn, melt, vapour, and solid. Everymetho~its own advantage, disadva nlagea nd problems. Oneof the problems in growth from solution is creeping up.Creeping up is undesirable growth or thin layer on the wallof crystal growth bath. Sometimes this layer grows very rapid andso fills the bath, and prevents growth . In this paper, thesesubjects are consideredl. Why does creeping up occure?2. What parameter affect on it?3. What in the best way ror its prevention?Experi ments show that creeping up is arrected by wettingang le between solution a nd bath wall, viscosity of solution,agitation, additives, and shape of bath.

Huntite mineral with formula CaMg3(C03}4 is anatural carbonatic material with rhombohedral system that itscomposition is between dolomite (CaMg(C03h) and magnesite.For the first time Huntite was found in American Nevadaprovince, then in other places i,e. Poland, Hungary, France,Australia, Iran and Greece.According to thermOdynamic, Huntite forms in condition oflow pressure and tcmpreature in the surface or near surface area.Investigation in Iran shows the existence ofHuntite mineralwithin weathered ultramafic rocks. At outer pan of eastern Iran,a great bulk of this rocks in ophiOlitic zone is origineted. Insome of this area outcrop of magnesite is in adjacent withHuntite.

Microscopic and XRD investigations indicate that themain mica is phlogopi!e. There are also a small amounl ofMuscovi!e in Ihe eas! pan. Trend of mica layers is NE-SW.Host rocks arc Gneiss, mi::.;!schist S, granite and gabbro.Minerals assemblage of this mine is phlogopitc, apatite andcalcite. Chemical and microscopical in vestiga tions of graniteindicate that they are nonorogen alkaligranitc type A The majorminerals are potass ic feldspars and albite (with mi croperthitetexture) and quartz (with micrograph ice tex ture). Garnel andcalcite are minor minerals. Phogopite, Apatite and calcite vein isresulted in pneumatoHte to hydrothermal phase from a graniticmelt with high Mg, K, Ca and P.

The new method of double dil ution can be used toa nalyse quantitatively all the phases of a multiphase systemwit hout the need to construct calibration curves, and with as fewas 2 or 3 mixtures prepa red for X-ray diffraction. A specificweight of the powdered specimen which is to be analysed, ismixed with a fixed proportion of internal standard. The standardcan be any crysta ll ine compou nd with a prefe rably symmetricalStruclUre, not present in the original specimen. The other part tobe mixed is a combi nation of finely ground pure phases ormaterials of known purity. Area under the diffracted peaks orintegra ted inte nsi ty h measured. At least twO X-ray samples ofknown and different proportions shou ld be employed.Intcnsily ratiO, Y axis, is plotted against weight ratio, X axis,so that a linea r plol for combina tion of 2 peaks from each phaseand standard is plaited. Required phase is read from thein tercept of the abscfssu. Mathematics of lilt:: m4!thod Is ctlscussc<1with a n example of determining alumina, mullite. q uartz a ndsilicon in a ceramic test piece containing glassy phase